'bacteriophobia' originates from a modern combining form: 'bacterio-' (from Greek 'bakterion', where 'bakterion' meant 'small staff' or 'rod') and 'phobia' (from Greek 'phobos', where 'phobos' meant 'fear').

'bacteriophobia' developed as a Modern English compound: Greek 'bakterion' passed into New Latin as 'bacterium' and produced the combining form 'bacterio-'; Greek 'phobos' entered English via New Latin as 'phobia'; these elements combined in Modern English to form 'bacteriophobia'.

Initially the roots referred specifically to 'rod-shaped organisms' ('bakterion') and 'fear' ('phobos'), but combined they came to mean the more general 'fear of bacteria' in contemporary usage.