function (math.)

a piece of written or electronic correspondence

to teach by correspondence

to send a letter

letters or items of mail

an incoming letter or piece of correspondence, typically formal

a written reply

The wave function of a quantum mechanical system.

A strategic mountain pass in modern-day Henan Province, forming the eastern gateway of the Qin State during the Warring States Period (770-221 BC).

linear function (math.)

formal written letter or correspondence

Hakodate, main port of south Hokkaidō, Japan

inverse function (math.)

an informal letter or memorandum sent by an organization

a formal letter written to express congratulations

even function (math.)

odd function (math.)

to purchase by mail; mail order

the derived function or derivative f' of a function f

generating function (math.)

functor (math.)

An anonymous letter containing malicious accusations or threats (Taiwanese usage).

a message of condolence

to send a formal letter or official circular to inform or communicate.

callback function (computing)

the trigonometric functions

(geology) the earth's mantle (Taiwan usage)

function of a complex variable

(math.) theory of functions of a complex variable

multivalued function (math.)

to bring to justice; to hand over to the law

function of a real variable (math.)

theory of functions of a real variable

to inform, notify, or submit official documents through formal written correspondence

spline function (math.)

(math.) elliptic function

library (computer software)