'Aquarian' originates from Latin, specifically the word 'Aquarius', where 'aqua' meant 'water' and the suffix '-arius' indicated connection or belonging.

'Aquarius' in Latin (meaning 'water-bearer') passed into New Latin and later into English; the English adjective/noun 'Aquarian' developed from that Latin form to denote someone or something relating to Aquarius.

Initially it referred directly to the 'water-bearer' (a figure associated with water); over time it came to mean specifically someone born under the zodiac sign Aquarius or things relating to that sign (and, by extension, to the Age of Aquarius and its associated ideas).