com-

in Latin, the form of com- "together, with" in compounds with stems beginning in vowels, h-, and gn-; see com-. Taken in English from 17c. as a living prefix meaning "together, mutually, in common," and used promiscuously with native words (co-worker) and Latin-derived words not beginning with vowels (codependent), including some already having it (co-conspirator).

with year-dates, an occasional Roman method of identifying a given year by reference to the time passed since founding of the city, which in 1c. B.C.E. was calculated to have taken place in what we would call 753 B.C.E. Literally "from the city founded;" the elements are ab "from" (see ab-) + ablative of urbs "city" (see urban) + fem. past participle of condere "put together, store," from assimilated form of com- "together" (see com-) + -dere "put" (from PIE root *dhe- "to put, place").