Dictionary.com Unabridged (v 1.1) - Cite This Source - Share This

American Heritage Dictionary - Cite This Source - Share This

func·tion       (fŭngk'shən)  Pronunciation Key  n.   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. A 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. 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. Abbr. f Mathematics A 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. 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. intr.v.   func·tioned, func·tion·ing, func·tions To have or perform a function; serve: functioned as ambassador. [Latin fūnctiō, fūnctiōn-, performance, execution, from fūnctus, past participle of fungī, to perform, execute.] func'tion·less adj. Synonyms: These nouns denote the actions and activities assigned to, required of, or expected of a person: the function of a teacher; a bank clerk's duty; assumed the office of financial adviser; the role of a parent.

Online Etymology Dictionary - Cite This Source - Share This
function  (n.)

WordNet - Cite This Source - Share This

function
noun
1.	(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)
2.	what something is used for; "the function of an auger is to bore holes"; "ballet is beautiful but what use is it?"
3.	the actions and activities assigned to or required or expected of a person or group; "the function of a teacher"; "the government must do its part"; "play its role"
4.	a relation such that one thing is dependent on another; "height is a function of age"; "price is a function of supply and demand"
5.	a formal or official social gathering or ceremony; "it was a black-tie function"
6.	a vaguely specified social event; "the party was quite an affair"; "an occasion arranged to honor the president"; "a seemingly endless round of social functions" [syn: affair]
7.	a set sequence of steps, part of larger computer program [syn: routine]
verb
1.	perform as expected when applied; "The washing machine won't go unless it's plugged in"; "Does this old car still run well?"; "This old radio doesn't work anymore" [ant: malfunction]
2.	serve a purpose, role, or function; "The tree stump serves as a table"; "The female students served as a control group"; "This table would serve very well"; "His freedom served him well"; "The table functions as a desk" [syn: serve]
3.	perform duties attached to a particular office or place or function; "His wife officiated as his private secretary" [syn: officiate]

The American Heritage Science Dictionary - Cite This Source - Share This

function       (fŭngk'shən)  Pronunciation Key  A relationship between two sets that matches each member of the first set with a unique member of the second set. Functions are often expressed as an equation, such as y = x + 5, meaning that y is a function of x such that for any value of x, the value of y will be 5 greater than x. A quantity whose value depends on the value given to one or more related quantities. For example, the area of a square is a function of the length of its sides.

American Heritage New Dictionary of Cultural Literacy, Third Edition - Cite This Source - Share This
function

In mathematics, a quantity whose value is determined by the value of some other quantity. For example, ®ÄúThe yield of this field is a function of the amount of fertilizer applied®Äù means that a given amount of fertilizer will yield an amount of whatever crop is growing.

American Heritage Stedman's Medical Dictionary - Cite This Source - Share This

function func·tion (fŭngk'shən)
n.

1. The physiological property or the special action of an organ or a body part.
2. Something closely related to another thing and dependent on it for its existence, value, or significance, such as growth resulting from nutrition.
3. A mathematical variable so related to another that for each value assumed by one there is a value determined for the other.
4. 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.
5. 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.
6. A particular reactive grouping in a molecule.

Free On-line Dictionary of Computing - Cite This Source - Share This

function
1. (Or "map", "mapping") If D and C are sets (the domain and codomain) then a function f from D to C, normally written "f : D -> C" is a subset of D x C such that:
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.
2. Computing usage derives from the mathematical term but is much less strict. In programming (except in functional programming), a function may return different values each time it is called with the same argument values and may have side effects.
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.
(1996-09-01)

Webster's Revised Unabridged Dictionary - Cite This Source - Share This

Function

Func"tion\, n. [L. functio, fr. fungi to perform, execute, akin to Skr. bhuj to enjoy, have the use of: cf. F. fonction. Cf. Defunct.]

1. The act of executing or performing any duty, office, or calling; per formance. "In the function of his public calling." --Swift.

2. (Physiol.) The appropriate action of any special organ or part of an animal or vegetable organism; as, the function of the heart or the limbs; the function of leaves, sap, roots, etc.; life is the sum of the functions of the various organs and parts of the body.

3. The natural or assigned action of any power or faculty, as of the soul, or of the intellect; the exertion of an energy of some determinate kind.

As the mind opens, and its functions spread. --Pope.

4. The course of action which peculiarly pertains to any public officer in church or state; the activity appropriate to any business or profession.

Tradesmen . . . going about their functions. --Shak.

The malady which made him incapable of performing his regal functions. --Macaulay.

5. (Math.) A quantity so connected with another quantity, that if any alteration be made in the latter there will be a consequent alteration in the former. Each quantity is said to be a function of the other. Thus, the circumference of a circle is a function of the diameter. If x be a symbol to which different numerical values can be assigned, such expressions as x^2, 3^x, Log. x, and Sin. x, are all functions of x.

Algebraic function, a quantity whose connection with the variable is expressed by an equation that involves only the algebraic operations of addition, subtraction, multiplication, division, raising to a given power, and extracting a given root; -- opposed to transcendental function.

Arbitrary function. See under Arbitrary.

Calculus of functions. See under Calculus.

Carnot's function (Thermo-dynamics), a relation between the amount of heat given off by a source of heat, and the work which can be done by it. It is approximately equal to the mechanical equivalent of the thermal unit divided by the number expressing the temperature in degrees of the air thermometer, reckoned from its zero of expansion.

Circular functions. See Inverse trigonometrical functions (below). -- Continuous function, a quantity that has no interruption in the continuity of its real values, as the variable changes between any specified limits.

Discontinuous function. See under Discontinuous.

Elliptic functions, a large and important class of functions, so called because one of the forms expresses the relation of the arc of an ellipse to the straight lines connected therewith.

Explicit function, a quantity directly expressed in terms of the independently varying quantity; thus, in the equations y = 6x^2, y = 10 -x^3, the quantity y is an explicit function of x.

Implicit function, a quantity whose relation to the variable is expressed indirectly by an equation; thus, y in the equation x^2 + y^2 = 100 is an implicit function of x.

Inverse trigonometrical functions, or Circular function, the lengths of arcs relative to the sines, tangents, etc. Thus, AB is the arc whose sine is BD, and (if the length of BD is x) is written sin ^-1x, and so of the other lines. See Trigonometrical function (below). Other transcendental functions are the exponential functions, the elliptic functions, the gamma functions, the theta functions, etc.

One-valued function, a quantity that has one, and only one, value for each value of the variable. -- Transcendental functions, a quantity whose connection with the variable cannot be expressed by algebraic operations; thus, y in the equation y = 10^x is a transcendental function of x. See Algebraic function (above). -- Trigonometrical function, a quantity whose relation to the variable is the same as that of a certain straight line drawn in a circle whose radius is unity, to the length of a corresponding are of the circle. Let AB be an arc in a circle, whose radius OA is unity let AC be a quadrant, and let OC, DB, and AF be drawnpependicular to OA, and EB and CG parallel to OA, and let OB be produced to G and F. E Then BD is the sine of the arc AB; OD or EB is the cosine, AF is the tangent, CG is the cotangent, OF is the secant OG is the cosecant, AD is the versed sine, and CE is the coversed sine of the are AB. If the length of AB be represented by x (OA being unity) then the lengths of Functions. these lines (OA being unity) are the trigonometrical functions of x, and are written sin x, cos x, tan x (or tang x), cot x, sec x, cosec x, versin x, coversin x. These quantities are also considered as functions of the angle BOA.

Webster's Revised Unabridged Dictionary - Cite This Source - Share This

Function

Func"tion\, Functionate \Func"tion*ate\, v. i. To execute or perform a function; to transact one's regular or appointed business.

Webster's Revised Unabridged Dictionary - Cite This Source - Share This

Function

Func"tion\, n. 1. (Eccl.) A religious ceremony, esp. one particularly impressive and elaborate.

Every solemn `function' performed with the requirements of the liturgy. --Card. Wiseman.

2. A public or social ceremony or gathering; a festivity or entertainment, esp. one somewhat formal.

This function, which is our chief social event. --W. D. Howells.