'bacteriology' originates from New Latin, specifically the word 'bacteriologia', where 'bacterium' (from Greek 'bakterion') meant 'small staff, rod' and '-logy' (from Greek 'logia') meant 'study of'.

'bacteriology' changed from New Latin 'bacteriologia' (and via French 'bactériologie') and eventually became the modern English word 'bacteriology'.

Initially, it meant 'the study of bacteria', and over time this core meaning has been retained in modern usage.