'bacteraemia' originates from New Latin and Greek, specifically the Greek word 'bakterion' where 'bakter-' meant 'small staff' (used for rod-shaped bacteria) and the Greek 'haima' via New Latin '-aemia' meant 'blood'.

'bacteraemia' changed from New Latin/Modern scientific formations such as 'bacteremia' (coined in the 19th century from 'bacterium' + '-emia') and eventually existed in English as the variant spellings 'bacteraemia' and 'bacteremia'.

Initially, it meant 'the presence of bacteria in the blood', and this core medical meaning has remained largely unchanged, now used in clinical and microbiological contexts to denote bacteria detected in the bloodstream.