'dehydrogenise' originates from the prefix 'de-' (Latin), the noun 'hydrogen' (from Greek elements 'hydro-' meaning 'water' and '-genes' meaning 'producing' or 'originating'), and the verb-forming suffix '-ise' (from French/Latin).

'hydrogen' entered scientific English from French 'hydrogène' (itself from Greek 'hydro-' + 'genes') in the late 18th century; the productive Latin/Neo-Latin prefix 'de-' was combined with 'hydrogen' to form verbs like 'dehydrogenate'/'dehydrogenise', and the modern English verb 'dehydrogenise' (UK) / 'dehydrogenize' (US) developed from these scientific coinages.

Initially the components referred specifically to 'water-producer' (Greek roots) and the prefix 'de-' simply meant 'remove' or 'reverse'; over time the combined form came to mean specifically 'to remove hydrogen (from a compound)' in chemical usage, a meaning that has remained stable in technical contexts.