(mathematics) a mathematical relation such that each element of a given set (the domain of the function) is associated with an element of another set (the range of the function)

- map,
- mathematical function,
- threshold function,
- exponential,
- multinomial,
- single-valued function,
- metric,
- mapping,
- mathematical relation,
- trigonometric function,
- operator,
- Kronecker delta,
- exponential function,
- expansion,
- isometry,
- circular function,
- metric function,
- transformation,
- polynomial,
- inverse function

what something is used for

based on the meter as a standard of measurement

a formal or official social gathering or ceremony

a system of related measures that facilitates the quantification of some particular characteristic

a vaguely specified social event