'bacillicide' originates from New Latin/modern scientific coinage, formed from the Latin 'bacillus' (a diminutive of 'baculum', meaning 'stick' or 'rod') and the suffix '-cide' ultimately from Latin 'caedere' meaning 'to kill'.

'bacillus' comes from Latin 'bacillum' (a little rod) derived from 'baculum' ('stick'); the suffix '-cide' derives from Latin 'caedere' ('to kill') and entered English scientific vocabulary via Neo-Latin and French-influenced formations; these elements were combined in modern English to form 'bacillicide'.

Originally the components referred literally to 'rod' (bacillus) and 'killing' (-cide); the combined modern meaning is specifically 'a substance or agent that kills bacilli (rod-shaped bacteria)'.