[Imitative. Cf. BUMBO.]
† a. A childs word for drink (cf. BUM v.1). Obs. b. Sc. To say neither ba nor bum: not to say a word (cf. BAFF).
1552. Huloet, Bua, the terme or voyce of infantes, askynge drynke, englyshed yf ye wyll, Bumme.
1570. Levins, Manip., 187. Bum, drinke, potus.
1598. Tom Tytler & W. (1661), 4. Tipple (arriving with liquor) here is good bum, I dare boldly say.
1861. Ramsay, Remin., iv. (ed. 18), 75. They neither said ba nor bum.