The Latin phrase ad hoc translates as “toward this”, and is used in mathematics to describe anything that has been made up specifically for one particular purpose.

## Examples

1. 1.

an ad hoc definition is a temporary definition that might be useful for the discussion at hand. For instance, let a nice set be a closed set with smooth boundary.

2. 2.

If a proof makes use of an ad hoc construction, the proof (typically) does not make use of a general theory for the problem.