'hydrological' originates from New Latin/Modern English formation based on 'hydrology', ultimately from Greek elements: 'hydro-' from Greek 'hudōr' meaning 'water' and '-logy' from Greek 'logia' meaning 'study'.

'hydrological' developed from the noun 'hydrology' (New Latin 'hydrologia'), which itself was formed from Greek roots ('hudōr' + 'logia'); the adjective was produced by adding the English suffix '-ical' to create 'hydrological'.

Initially linked to the term for the scientific study of water, its usage broadened to describe processes, measurements, and attributes related to water and the water cycle.