'bifunctional' originates from Latin elements: the prefix 'bi-' (from Latin 'bis') meaning 'two', combined with 'functional' (from Late Latin 'functionalis', from Latin 'functio').

'bifunctional' is a modern English formation by combining the Latin-derived prefix 'bi-' + the adjective 'functional'; it emerged in scientific and technical usage in the 20th century and became the established English term 'bifunctional'.

Initially formed to mean 'having two functions' in a general sense, the term's use expanded in scientific contexts to describe molecules, catalysts, or proteins with two distinct functional groups or activities; the core idea of 'two functions' has been retained.