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.
1844, "perform a function" (intransitive), from function (n.). Related: Functioned; functioning.
initialism (acronym) of Southern Christian Leadership Conference, founded 1957 by the Rev. Martin Luther King Jr., Bayard Rustin, and others.
"witches' sabbath," a midnight meeting supposed to have been held annually by demons, sorcerers, and witches under the leadership of Satan, to celebrate their orgies, 1650s, a special application of the French form of Sabbath (q.v.).