'counterflow' originates from English, specifically formed as a compound of 'counter-' and 'flow', where 'counter-' (from Old French and ultimately Latin 'contra') meant 'against' and 'flow' (from Old English 'flōwan') meant 'to flow'.

'counterflow' changed from the earlier hyphenated form 'counter-flow' used in 19th and early 20th century technical writing and eventually became the single word 'counterflow' in modern usage.

Initially, it simply meant 'a flow that goes against another flow'; over time the term also developed a specialized technical sense (for example, in engineering and thermodynamics) referring to arrangements where two streams move in opposite directions to improve transfer efficiency.