| 1 | English | bacillus | Any of various rod-shaped, spore-forming aerobic... |
| 2 | Latin | bacillus | Alternative form of bacillum; rod-shaped... |
| 3 | Latin | bacillum | A small staff or wand; The shaft or handle of a... |
| 4 | Latin | baculum | walking stick, cane, staff; sceptre, rod; a... |
| 5 | Proto-Indo-European | baḱ- | club, pointed stick, peg; pointed stick, peg |