1300-50; < Latinquotīdiānus, cottīdiānus daily, equivalent to cottīdi(ē) every day (adv.) (*quot(t)ī a locative form akin to quot however many occur, every + diē, ablative of diēs day; cf. meridian) + -ānus-an; replacing Middle Englishcotidien < Old French < Latin, as above
mid-14c., "everyday, daily," from Old French cotidian (Modern French quotidien), from Latin quotidianus "daily," from Latin quotus "how many? which in order or number?" (see quote (v.)) + dies "day" (see diurnal). Meaning "ordinary, commonplace, trivial" is from mid-15c.