Middle English prechen, "deliver a sermon, proclaim the Gospel," from late Old English predician, a loan word from Church Latin; reborrowed 12c. as preachen, from Old French preechier "to preach, give a sermon" (11c., Modern French précher), from Late Latin praedicare "to proclaim publicly, announce" (in Medieval Latin "to preach," source also of Spanish predicar), from Latin prae "before" (from PIE root *per- (1) "forward," hence "in front of, before") + dicare "to proclaim, to say" (from PIE root *deik- "to show," also "pronounce solemnly," and see diction). Related: Preached; preaching.
Meaning "give earnest advice, especially on moral subjects" is by 1520s. To preach to the converted is recorded from 1867 (the form preach to the choir attested from 1979).
updated on October 20, 2020