In orthography and typography, letter case (or just case) is the distinction between the letters that are in larger upper case (also capital letters, capitals, caps, large letters, or more formally majuscule (see Terminology) and smaller lower case (also small letters, or more formally minuscule, see Terminology) in the written representation of certain languages. Here is a comparison of the upper and lower case versions of each letter included in the English alphabet (the exact representation will vary according to the font used):
Typographically, the basic difference between the majuscules and minuscules is not that the majuscules are big and minuscules small, but that the majuscules generally have the same height. The height of the minuscules varies, as some of them have parts higher or lower than the average, i.e. ascenders and descenders. In Times New Roman, for instance, b, d, f, h, k, l, t  are the letters with ascenders, and g, j, p, q, y are the ones with descenders. Further to this, with old-style numerals still used by some traditional or classical fonts—although most do have a set of alternative Lining Figures— 6 and 8 make up the ascender set, and 3, 4, 5, 7 and 9 the descender set.
Letter case is often prescribed by the grammar of a language or by the conventions of a particular discipline. In orthography, the uppercase is primarily reserved for special purposes, such as the first letter of a sentence or of a proper noun, which makes the lowercase the more common variant in text. In mathematics, letter case may indicate the relationship between objects with uppercase letters often representing "superior" objects (e.g. X could be a set containing the generic member x). Engineering design drawings are typically labelled entirely in upper-case letters, which are easier to distinguish than lowercase, especially when space restrictions require that the lettering be small.
- Terminology 1
Bicameral script 2
- Capitalisation 2.1
- Exceptional letters and digraphs 2.2
- Related phenomena 2.3
Stylistic or specialised usage 3
Case styles 3.1
- Headings and publication titles 3.1.1
- Special case styles 3.1.2
- Metric system 3.2
- Case styles 3.1
Case folding 4
- Methods in word processing 4.1
- Methods in programming 4.2
- Unicode case folding and script identification 4.3
- Type cases 5.1
- See also 6
- References 7
- External links 8
The terms upper case and lower case can be written as two consecutive words, connected with a hyphen (upper-case and lower-case), or as a single word (uppercase and lowercase). These terms originated from the common layouts of the shallow drawers called type cases used to hold the movable type for letterpress printing. Traditionally, the capital letters were stored in a separate case that was located above the case that held the small letters, and the name proved easy to remember since capital letters are taller.
Majuscule, ( or ), for palaeographers, is technically any script in which the letters have very few or very short ascenders and descenders, or none at all (for example, the majuscule scripts used in the Codex Vaticanus Graecus 1209, or the Book of Kells). By virtue of their visual impact, this made the term majuscule an apt descriptor for what much later came to be more commonly referred to as uppercase letters.
Minuscule refers to lowercase letters. The word is often spelled miniscule, by association with the unrelated word miniature and the prefix mini-. This has traditionally been regarded as a spelling mistake (since minuscule is derived from the word minus), but is now so common that some dictionaries tend to accept it as a nonstandard or variant spelling. Miniscule is still less likely, however, to be used in reference to lower-case letters.
Most Georgian alphabet is special since it used to be bicameral, but today is mostly used in a unicameral way.
If an alphabet has letter case, all or nearly all letters have both forms. Paired forms are considered variants of the same letter: they have the same name and pronunciation and will be treated identically when sorting in alphabetical order. The glyphs of lower-case letters can resemble smaller forms of the upper-case glyphs restricted to the base band (e.g. "C/c" and "S/s", cf. small caps) or can look hardly related (e.g. "D/d" and "G/g").
In scripts with a case distinction, lower case is generally used for the majority of text; capitals are used for capitalisation and emphasis. In addition, acronyms and initialisms are often written in all-caps, depending on various factors in English.
Capitalisation is the writing of a word with its first letter in uppercase and the remaining letters in lowercase. Capitalisation rules vary by language and are often quite complex, but in most modern languages that have capitalisation, the first word of every sentence is capitalised, as are all proper nouns.
Capitalisation in English, in terms of the general orthographic rules independent of context (e.g. title vs. heading vs. text), is universally standardized for formal writing. (Informal communication, such as texting, instant messaging or a handwritten sticky note, may not bother, but that is because its users usually do not expect it to be formal.) In English, capital letters are used as the first letter of a sentence, a proper noun, or a proper adjective. There are a few pairs of words of different meanings whose only difference is capitalisation of the first letter. The names of the days of the week and the names of the months are also capitalised, as are the first-person pronoun "I" and the interjection "O" (although the latter is uncommon in modern usage, with "oh" being preferred). Other words normally start with a lower-case letter. There are, however, situations where further capitalisation may be used to give added emphasis, for example in headings and titles (see below). In some traditional forms of poetry, capitalisation has conventionally been used as a marker to indicate the beginning of a line of verse independent of any grammatical feature.
Other languages vary in their use of capitals. For example, in German all nouns are capitalised (this was previously common in English as well), while in Romance and most other European languages the names of the days of the week, the names of the months, and adjectives of nationality, religion and so on normally begin with a lower-case letter.
Exceptional letters and digraphs
- The German letter "ß" orthographically only exists in lower case, as it never occurs at the beginning of a word. In all-caps style "ß" is normally replaced by the digraph "SS" (but see Capital ß).
- The Greek upper-case letter "Σ" has two different lower-case forms: "ς" in word-final position and "σ" elsewhere. In a similar manner, the Latin upper-case letter "S" used to have two different lower-case forms: "s" in word-final position and "ſ" elsewhere. The latter form, called the long s, fell out of general use before the middle of the 19th century, except for the countries that continued to use Blackletter typefaces such as Fraktur. When Blackletter type fell out of general use in the mid-20th century, even those countries dropped the long s.
- The Cyrillic letter "Ӏ" usually has only a capital form, which is also used in lower-case text.
- Unlike most Latin-script languages, which link the dotless upper-case "I" with the dotted lower-case "i", Turkish has both a dotted and dotless I in upper and lower case. Each of the two pairs ("İ/i" and "I/ı") represent a distinctive phoneme.
- In some languages, specific digraphs may be regarded as a single letter. For example, in Slavic languages whose orthography is coordinated for the Cyrillic and Latin script, the Latin digraphs "ǈ/ǉ", "ǋ/ǌ" and "ǅ/ǆ" are each regarded as a single letter (like their Cyrillic equivalents "Љ/љ", "Њ/њ" and "Џ/џ", respectively), but even when capitalised, the second part resembles a lower-case letter (see discussion of "title case" below). Only in all-caps style should both parts resemble a capital letter (e.g. ǈiǉan–ǇIǇAN, ǋoǌa–ǊOǊA, ǅiǆa–ǄIǄA).
- In Dutch, the digraph "IJ/ij" is capitalised as a single entity (for example, "IJsland" rather than "Ijsland").
- In English (though not in Welsh), a name beginning with "ff" may be written in lower case, for example in a P. G. Wodehouse story "A Slice of Life" Wilfred Mulliner must circumvent the nasty Sir Jasper ffinch-ffarowmere to reach his love Angela.
Similar orthographic and graphostylistic conventions are used for emphasis or following language-specific rules, including:
- Font effects such as italic type or oblique type, boldface, and choice of serif vs. sans-serif.
- Typographical conventions in mathematical formulae include the use of Greek letters and the use of Latin letters with special formatting such as blackboard bold and blackletter.
- Letters of the Arabic alphabet and some jamo of the Korean hangul have different forms for initial or final placement, but these rules are strict and the different forms cannot be used for emphasis.
- In Mkhedruli in a fashion that is reminiscent of the usage of upper-case letters in the Latin, Greek, and Cyrillic alphabets.
- In the Japanese writing system, an author has the option of switching between kanji, hiragana, katakana, and rōmaji. In particular, every hiragana character has an equivalent katakana character, and vice-versa. Because this resembles the Latin alphabet's two cases, romanised Japanese sometimes uses lowercase letters to represent words that would be written in hiragana, and uppercase letters to represent words that would be written in katakana. Some kana syllabograms can be written in smaller type when they modify or combine with the preceding sign (yōon and sokuon).
Stylistic or specialised usage
In English, a variety of case styles are used in various circumstances:
- Sentence case
"The quick brown fox jumps over the lazy dog."
The standard case used in English prose. Only the first character is capitalised, except for proper nouns and other words which are generally capitalised by a more specific rule. Generally equivalent to the baseline universal standard of formal English orthography mentioned above.
- Title case
"The Quick Brown Fox Jumps Over [T/t]he Lazy Dog."
Also known as "headline style" and "capital case". First character in all words capitalised, except for certain subsets defined by rules that are not universally standardised. The standardisation is only at the level of house styles and individual style manuals. (See further explanation below at Headings and publication titles.) A simplified variant is start case, where all words, including articles, prepositions, and conjunctions, start with a capital letter.
- All caps
"THE QUICK BROWN FOX JUMPS OVER THE LAZY DOG."
Also known/written as "all-caps". Capital letters only. This style can be used in headings and special situations, such as for typographical emphasis in text made on a typewriter. With the advent of the Internet, all-caps is more often used for emphasis; however, it is considered poor netiquette by some to type in all capitals, and said to be tantamount to shouting. Long spans of Latin-alphabet text in all upper-case are harder to read because of the absence of the ascenders and descenders found in lower-case letters, which can aid recognition.
- Small caps
"the quick brown fox jumps over the lazy dog."
Capital letters at the size of a lowercase "x". Slightly larger small-caps can be used in a Mixed Case fashion. Used for acronyms, names, mathematical entities, computer commands in printed text, business or personal printed stationery letterheads, and other situations where a given phrase needs to be distinguished from the main text.
"the quick brown fox jumps over the lazy dog."
No capital letters. This style is sometimes used for artistic effect, such as in poetry. Also commonly seen in computer commands and SMS language, to avoid pressing the Shift key in order to type quickly.
|All-caps||THE||VITAMINS||ARE||IN||MY||FRESH||CALIFORNIA||RAISINS||all letters uppercase|
|Start case||The||Vitamins||Are||In||My||Fresh||California||Raisins||all words capitalised regardless of function|
|Title case||The||Vitamins||Are||in||My||Fresh||California||Raisins||first word and all other words capitalised except for articles, prepositions and conjunctions|
|The||Vitamins||are||in||My||Fresh||California||Raisins||as above and also excepting copulae (forms of "to be")|
|The||Vitamins||are||in||my||Fresh||California||Raisins||as above but excepting all closed-class words|
|German-style sentence case||The||Vitamins||are||in||my||fresh||California||Raisins||first word and all nouns capitalised|
|German-style mid-sentence case||the||Vitamins||are||in||my||fresh||California||Raisins||all nouns capitalised (but not first word by default)|
|Sentence case||The||vitamins||are||in||my||fresh||California||raisins||first word, proper nouns and some specified words capitalised|
|Mid-sentence case||the||vitamins||are||in||my||fresh||California||raisins||as above, but first word not capitalised by default|
|Lowercase||the||vitamins||are||in||my||fresh||california||raisins||all letters lowercase (unconventional in English)|
Headings and publication titles
In English-language publications, varying conventions are used for capitalising words in publication titles and headlines, including chapter and section headings. The rules differ substantially between individual house styles.
The convention followed by many British International Organization for Standardization.
As regards publication titles it is, however, a common typographic practice among both British and U.S. publishers to capitalise significant words (and in the United States, this is often applied to headings, too). This family of typographic conventions is usually called title case. For example, R. M. Ritter's Oxford Manual of Style (2002) suggests capitalising "the first word and all nouns, pronouns, adjectives, verbs and adverbs, but generally not articles, conjunctions and short prepositions". This is an old form of emphasis, similar to the more modern practice of using a larger or boldface font for titles. The rules for which words to capitalise are not based on any grammatically inherent correct/incorrect distinction and are not universally standardized; they are arbitrary and differ between style guides, although in most styles they tend to follow a few strong conventions, as follows:
- Most styles capitalise all words except for closed-class words (certain parts of speech, namely, articles, prepositions, and conjunctions); but the first word (always) and last word (in many styles) are also capped, regardless of part of speech. Many styles capitalise longer prepositions such as "between" or "throughout", but not shorter ones such as "for" or "with". Among such styles, "four or more letters (≥4)" or "more than four letters (>4)" are the typical (although arbitrary and conflicting) threshold rules.
- A few styles capitalise all words in title case (the so-called start case), which has the advantage of being easy to implement and hard to get "wrong" (that is, "not edited to style"). Because of this rule's simplicity, software case-folding routines can handle 95% or more of the editing, especially if they are programmed for desired exceptions (such as "FBI not Fbi").
- As for whether hyphenated words are capitalised not only at the beginning but also after the hyphen, there is no universal standard; variation occurs in the wild and among house styles (e.g., "The Letter-Case Rule in My Book"; "Short-term Follow-up Care for Burns"). Traditional copyediting makes a distinction between temporary compounds (such as many nonce [novel instance] compound modifiers), in which every word is capped (e.g., "How This Particular Author Chose to Style His Autumn-Apple-Picking Heading"), and permanent compounds, which are terms that, although compound and hyphenated, are so well established that dictionaries enter them as headwords (e.g., "Short-term Follow-up Care for Burns").
Although title case is still widely used in English-language publications, especially in the United States, it is widely understood that it is a design choice rather than a requirement of orthographic correctness. Sometimes users decide not to bother with its arbitrariness (or even feel that it looks old-fashioned). It does impose a cost to enforce the rules and exceptions of any particular house style that, because of its arbitrariness, does not add any inherent value to the text.
In creative typography, such as music record covers and other artistic material, all styles are commonly encountered, including all-lowercase letters and special case styles, such as studly caps (see below). For example, in video-game wordmarks it is not uncommon to use stylized upper-case letters at the beginning and end of a title, with the intermediate letters in small caps or lower case (e.g., ArcaniA, ArmA, DmC; this style has also been adopted for use with the logo of WorldHeritage).
Special case styles
Spaces and punctuation are removed and the first letter of each word is capitalised. If this includes the first letter of the first word ("CamelCase", "PowerPoint", "TheQuick...", etc.), the case is sometimes called upper camel case (or, when written, "CamelCase"), Pascal case or bumpy case. When, otherwise, the first letter of the first word is lowercase ("camelCase", "iPod", "eBay", etc.), the case is usually known as camelCase and sometimes as lower camel case. This is the format that has become popular in the branding of information technology products.
Punctuation is removed and spaces are replaced by single underscores. Normally the letters share the same case (e.g. "UPPER_CASE_EMBEDDED_UNDERSCORE" or "lower_case_embedded_underscore") but the case can be mixed. When all upper case, it may be referred to as "SCREAMING_SNAKE_CASE". For Python private constants, __SCREAMING_SNAKES_ON_A_PLANE__ is sometimes used.
- kebab-case (spinal-case, Train-Case)
As per snake_case above, except hyphens rather than underscores are used to replace spaces. If every word is capitalized, the style is known as Train-Case.
Mixed case with no semantic or syntactic significance to the use of the capitals. Sometimes only vowels are upper-case, at other times upper and lower case are alternated, but often it is just random. The name comes from the sarcastic or ironic implication that it was used in an attempt by the writer to convey their own coolness. (It is also used to mock the violation of standard English case conventions by marketers in the naming of computer software packages, even when there is no technical requirement to do so – e.g. Sun Microsystems' naming of a windowing system NeWS.)
In the International System of Units (SI), a letter usually has a different meaning in upper and lower case when used as a unit symbol. By default, a unit symbol is written in lower case, but if the name of the unit is derived from a proper noun, the first letter of the symbol is written in upper case (nevertheless, the name of the unit, if spelled out, is always considered a common noun and written accordingly):
- 1 s (one second) when used for the base unit of time.
- 1 S (one siemens) when used for the unit of electric conductance and admittance (named after Werner von Siemens).
- 1 Sv (one sievert), used for the unit of ionising radiation dose (named after Rolf Maximilian Sievert).
For clarity, the symbol for litre can optionally be written in upper case even though the name is not derived from a proper noun:
- 1 l, the original form, where "one" and "elle" look rather alike.
- 1 L, the optional form, where "one" and "capital L" look different.
The letter case of a prefix symbol is defined independently of the unit symbol it is attached to. Lower case is used for all submultiple prefix symbols and the small multiple prefix symbols up to "k" (for kilo, meaning 103 = 1000 multiplier), whereas upper case is used for larger multipliers:
- 1 ms, a small measure of time ("m" for milli, meaning 10−3 = 1/1000 multiplier).
- 1 Ms, a large measure of time ("M" for mega, meaning 106 = 1 000 000 multiplier).
- 1 mS, a small measure of electric conductance.
- 1 MS, a large measure of electric conductance.
- 1 mm, a small measure of length (the latter "m" for metre).
- 1 Mm, a large measure of length.
Case-insensitive operations are sometimes said to fold case, from the idea of folding the character code table so that upper- and lower-case letters coincide. The conversion of letter case in a string is common practice in computer applications, for instance to make case-insensitive comparisons. Many high-level programming languages provide simple methods for case folding, at least for the ASCII character set.
Methods in word processing
Most modern word processors provide automated case folding with a simple click or keystroke. For example, in Microsoft Office Word, there is a dialog box for toggling the selected text through UPPERCASE, then lowercase, then Title Case (actually start caps; exception words must be lowercased individually). The keystroke shift-F3 does the same thing.
Methods in programming
In some forms of BASIC there are two methods for case folding:
UpperA$ = UCASE$("a") LowerA$ = LCASE$("A")
char upperA = toupper('a'); char lowerA = tolower('A');
#define toupper(c) (islower(c) ? (c) – 'a' + 'A' : (c)) #define tolower(c) (isupper(c) ? (c) – 'A' + 'a' : (c))
This only works because the letters of upper and lower cases are spaced out equally. In ASCII they are consecutive, whereas with EBCDIC they are not; nonetheless the upper-case letters are arranged in the same pattern and with the same gaps as are the lower-case letters, so the technique still works.
Some computer programming languages offer facilities for converting text to a form in which all words are first-letter capitalised. Visual Basic calls this "proper case"; Python calls it "title case". This differs from usual title casing conventions, such as the English convention in which minor words are not capitalised.
Unicode case folding and script identification
Unicode defines case folding through the three case-mapping properties of each character: uppercase, lowercase and titlecase. These properties relate all characters in scripts with differing cases to the other case variants of the character.
As briefly discussed in Unicode Technical Note #26, "In terms of implementation issues, any attempt at a unification of Latin, Greek, and Cyrillic would wreak havoc [and] make casing operations an unholy mess, in effect making all casing operations context sensitive […]". In other words, while the shapes of letters like A, B, E, H, K, M, O, P, T, X, Y and so on are shared between the Latin, Greek, and Cyrillic alphabets (and small differences in their canonical forms may be considered to be of a merely typographical nature), it would still be problematic for a multilingual character set or a font to provide only a single codepoint for, say, uppercase letter B, as this would make it quite difficult for a wordprocessor to change that single uppercase letter to one of the three different choices for the lower-case letter, b (Latin), β (Greek), or в (Cyrillic). Without letter case, a "unified European alphabet" – such as ABБCГDΔΕZЄЗFΦGHIИJ…Z, with an appropriate subset for each language – is feasible; but considering letter case, it becomes very clear that these alphabets are rather distinct sets of symbols.
Originally alphabets were written entirely in majuscule letters, spaced between well-defined upper and lower bounds. When written quickly with a pen, these tended to turn into rounder and much simpler forms. It is from these that the first minuscule hands developed, the half-uncials and cursive minuscule, which no longer stayed bound between a pair of lines. These in turn formed the foundations for the Carolingian minuscule script, developed by Alcuin for use in the court of Charlemagne, which quickly spread across Europe. The advantage of the minuscule over majuscule was improved, faster readability.
In Latin, papyri from Herculaneum dating before 79 AD (when it was destroyed) have been found that have been written in old Roman cursive, where the early forms of minuscule letters "d", "h" and "r", for example, can already be recognised. According to papyrologist Knut Kleve, "The theory, then, that the lower-case letters have been developed from the fifth century uncials and the ninth century Carolingian minuscules seems to be wrong." Both majuscule and minuscule letters existed, but the difference between the two variants was initially stylistic rather than orthographic and the writing system was still basically unicameral: a given handwritten document could use either one style or the other but these were not mixed. European languages, except for Ancient Greek and Latin, did not make the case distinction before about 1300.
The timeline of writing in Western Europe can be divided into four eras:
- Greek majuscule (9th–3rd century BC) in contrast to the Greek uncial script (3rd century BC – 12th century AD) and the later Greek minuscule
- Roman majuscule (7th century BC – 4th century AD) in contrast to the Roman uncial (4th–8th century BC), Roman Half Uncial, and minuscule
- Carolingian majuscule (4th–8th century AD) in contrast to the Carolingian minuscule (around 780 – 12th century)
- Gothic majuscule (13th and 14th century), in contrast to the early Gothic (end of 11th to 13th century), Gothic (14th century), and late Gothic (16th century) minuscules.
Traditionally, certain letters were rendered differently according to a set of rules. In particular, those letters that began sentences or nouns were made larger and often written in a distinct script. There was no fixed capitalisation system until the early 18th century. The English language eventually dropped the rule for nouns, while the German language kept it.
Similar developments have taken place in other alphabets. The lower-case script for the Greek alphabet has its origins in the 7th century and acquired its quadrilinear form in the 8th century. Over time, uncial letter forms were increasingly mixed into the script. The earliest dated Greek lower-case text is the Uspenski Gospels (MS 461) in the year 835. The modern practice of capitalising the first letter of every sentence seems to be imported (and is rarely used when printing Ancient Greek materials even today).
The individual type blocks used in hand typesetting are stored in shallow wooden or metal drawers known as "type cases". Each is subdivided into a number of compartments ("boxes") for the storage of different individual letters.
The Oxford Universal Dictionary on Historical Advanced Proportional Principles (reprinted 1952) indicates that case in this sense (referring to the box or frame used by a compositor in the printing trade) was first used in English in 1588. Originally one large case was used for each typeface, then "divided cases", pairs of cases for majuscules and minuscules, were introduced in the region of today's Belgium by 1563, England by 1588, and France before 1723.
The terms upper and lower case originate from this division. By convention, when the two cases were taken out of the storage rack, and placed on a rack on the compositor's desk, the case containing the capitals and small capitals stood at a steeper angle at the back of the desk, with the case for the small letters, punctuation and spaces being more easily reached at a shallower angle below it to the front of the desk, hence upper and lower case.
Though pairs of cases were used in English-speaking countries and many European countries in the seventeenth century, in Germany and Scandinavia the single case continued in use.
Various patterns of cases are available, often with the compartments for lower-case letters varying in size according to the frequency of use of letters, so that the commonest letters are grouped together in larger boxes at the centre of the case. The compositor takes the letter blocks from the compartments and places them in a composing stick, working from left to right and placing the letters upside down with the nick to the top, then sets the assembled type in a galley.
- In Roman Antiqua or other vertical fonts, the defunct Initial or Medial Long-s ‘ ſ ’ would have been an ascender, however, in italics, it could have been one of only two letters in the English or Expanded Latin Alphabet with both an ascender and a descender; the other being ‘ f ’ when italicized.
- RFC 1855 "Netiquette Guidelines"
- Online Text Case Converter: Convert to Title Case, Sentence Case, Uppercase & Lowercase
- Printing capitals worksheet
- Codex Vaticanus B/03 Detailed description of Codex Vaticanus Graecus 1209 with many images.
- All-caps is harder to read
- Capitals, a Primer of Information About Capitalization With Some Practical Typographic Hints as to The Use Of Capitals by Frederick W. Hamilton, 1918, from Project Gutenberg
- Lower Case Definition by The Linux Information Project; also includes information on lower case as it relates to computers.