'bactericide' originates from New Latin, formed from 'bacterium' (from Greek 'bakterion', meaning 'small staff' or 'rod') + the Latin-derived suffix '-cide' (from Latin 'caedere', meaning 'to kill').

'bacterium' comes from Greek 'bakterion' ('small staff' or 'rod'); New Latin adopted 'bacterium', and modern scientific English formed 'bactericide' by combining that stem with the Latin-derived suffix '-cide'.

Initially the components meant 'rod (bacterium)' and 'killer'; over time the combined form came to mean specifically 'an agent that kills bacteria'.