officiate

Borrowed from Latin officiātus, perfect participle of Late Latin officior (“to perform a function”) and of Medieval Latin officiō (“to officiate, say mass (9th cent.); to serve a church (13th cent.); to serve (early 13th c., 14th in British sources); to discharge an office (14th c.)”), from Latin officium (“official duty, service”), see -ate (verb-forming suffix). The noun is derived from Medieval Latin officiātus (“monk in charge of a monastic office, official (start of 12th c., 14th in British sources)”), substantivized from the participle, see -ate (noun-forming suffix).