Why is the ninth month called September?
1530s, "proper work or purpose," from Middle French fonction (16c.) and directly from Latin functionem (nominative functio) "performance, execution," noun of action from functus, past participle of fungi "perform, execute, discharge," from PIE root *bheug- (2) "to use, enjoy" (see brook (v.)). Use in mathematics probably begun by Leibnitz (1692).
1856, from function (n.). Related: Functioned; functioning.
function func·tion (fŭngk'shən)
The physiological property or the special action of an organ or a body part.
Something closely related to another thing and dependent on it for its existence, value, or significance, such as growth resulting from nutrition.
A mathematical variable so related to another that for each value assumed by one there is a value determined for the other.
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.
The general properties of a substance, depending on its chemical character and relation to other substances, that provide the basis upon which it may be grouped as among acids or bases.
A particular reactive grouping in a molecule.
In mathematics, a quantity whose value is determined by the value of some other quantity. For example, “The yield of this field is a function of the amount of fertilizer applied” means that a given amount of fertilizer will yield an amount of whatever crop is growing.
1. For each d in D there exists some c in C such that (d,c) is an element of f. I.e. the function is defined for every element of D.
2. For each d in D, c1 and c2 in C, if both (d,c1) and (d,c2) are elements of f then c1 = c2. I.e. the function is uniquely defined for every element of D.
See also image, inverse, partial function.
A procedure is a function which returns no value but has only side-effects. The C language, for example, has no procedures, only functions. ANSI C even defines a type, void, for the result of a function that has no result.