In military forces, leave is a permission to be away from one's unit, either for a specified or unspecified period of time.
Various militaries have specific rules that regulate leaves.
Block leave is a term used to refer to time allotted to be spent with families independently of their units and where they must not report to their units while on rotation from their tours.
A furlough is a term applied to members of an armed service who have been given an extended period of leave from front line service in order to return home. For example, during World War II New Zealand soldiers who had served overseas for long periods (usually three or more years) were granted a "furlough" for a visit home. These soldiers on leave were called "furlough men" 
- "Furlough Scheme | NZETC". Nzetc.victoria.ac.nz. Retrieved 2013-12-10.