1875, "announcement on a bill or poster," verbal noun from bill (v.) "post as a public notice" (see bill (n.1)); hence top billing (1928). Meaning "act of sending out a bill" is recorded from 1908.
billing (n.2)
"a dove-like caressing, love-making," 1580s; see bill (v.2).
billet
billet-doux
billfold
billiard
billiards
billing
billingsgate
billion
billionaire
billionth
billow