Uduality
String theory 

Fundamental objects 
Perturbative theory 
Nonperturbative results 
Phenomenology 
Mathematics 
Theorists

In physics, Uduality (short for unified duality)^{[1]} is a symmetry of string theory or Mtheory combining Sduality and Tduality transformations. The term is most often met in the context of the "Uduality (symmetry) group" of Mtheory as defined on a particular background space (topological manifold). This is the union of all the Sduality and Tduality available in that topology. The narrow meaning of the word "Uduality" is one of those dualities that can be classified neither as an Sduality, nor as a Tduality  a transformation that exchanges a large geometry of one theory with the strong coupling of another theory, for example.
References
 ^ S. Mizoguchi, "On discrete Uduality in Mtheory", 2000.