Old English bolla "pot, cup, bowl," from Proto-Germanic *bul- "a round vessel" (cf. Old Norse bolle, Old High German bolla), from PIE *bhl-, from root *bhel- (2) "to blow, inflate, swell" (see bole).
The sockets of the lamps of the golden candlestick of the tabernacle are called bowls (Ex. 25:31, 33, 34; 37:17, 19, 20); the same word so rendered being elsewhere rendered "cup" (Gen. 44:2, 12, 16), and wine "pot" (Jer. 35:5). The reservoir for oil, from which pipes led to each lamp in Zechariah's vision of the candlestick, is called also by this name (Zech. 4:2, 3); so also are the vessels used for libations (Ex. 25:29; 37:16).