# Domain

(1) In analysis, the domain of a function is the set of values for which a function is defined. (2) In topology, a domain is a connected, open set.

Domain is a high school-level concept that would be first encountered in a pre-calculus course covering functions. It is listed in the California State Standards for Algebra I.

### Prerequisites

Function: | A function is a relation that uniquely associates members of one set with members of another set. The term "function" is sometimes implicitly understood to mean continuous function, linear function, or function into the complex numbers. |