1530s, "one's proper work or purpose; power of acting in a specific proper way," from French fonction (16c.) and directly from Latin functionem (nominative functio) "a performance, an execution," noun of action from funct-, past-participle stem of fungi "perform, execute, discharge," from PIE *bhung- "be of use, be used" (source also of Sanskrit bhunjate "to benefit, make benefit, atone," Armenian bowcanem "to feed," Old Irish bongaid "to break, harvest"), which is perhaps related to root *bhrug- "to enjoy." Meaning "official ceremony" is from 1630s, originally in church use. Use in mathematics probably was begun by Leibnitz (1692). In reference to computer operations, 1947.
mid-15c., "concealed, secret," from Latin latentem (nominative latens) "lying hid, concealed, secret, unknown," present participle of latere "lie hidden, lurk, be concealed," from PIE *late-, suffixed form of root *lādh- "to be hidden" (source also of Greek lēthē "forgetfulness, oblivion," lēthargos "forgetful," lathre "secretly, by stealth," lathrios "stealthy," lanthanein "to be hidden;" Old Church Slavonic lajati "to lie in wait for"). Meaning "dormant, undeveloped" is from 1680s, originally in medicine.
1844, "perform a function" (intransitive), from function (n.). Related: Functioned; functioning.
"tending to become latent or obscure, not obvious to perception," 1836, from Latin latescentem (nominative latescens), present participle of latescere "to hide oneself, be hidden," inchoative of latere "to lie hidden" (see latent). Related: Latescence.
"one who has a certain function, one who holds an office," 1791, from or patterned on French fonctionnaire, a word of the Revolution; from fonction (see function (n.)). As an adjective in English from 1822, "functional." Related: Functionarism.