The action for which a person or thing is particularly fitted or employed. Assigned duty or activity. A specific occupation or role: in my function as chief editor. An official ceremony or a formal social occasion. Something closely related to another thing and dependent on it for its existence, value, or significance: Growth is a function of nutrition. Mathematics A variable so related to another that for each value assumed by one there is a value determined for the other. Mathematics A rule of correspondence between two sets such that there is a unique element in the second set assigned to each element in the first set. Biology The physiological activity of an organ or body part. Chemistry The characteristic behavior of a chemical compound, resulting from the presence of a specific functional group. Computer Science A procedure within an application. To have or perform a function; serve: functioned as ambassador.