'aquarian' originates from Latin, specifically the word 'aquarius', where 'aqua' meant 'water' and the suffix '-arius' meant 'pertaining to' or 'connected with'.

'aquarian' developed from the Latin word 'aquarius' (used in Late/Medieval Latin for the constellation and the 'water-carrier' figure) and entered English usage via New/Medieval Latin and later astronomical/astrological vocabulary to form the adjective and noun 'aquarian'.

Initially, it referred literally to a 'water-carrier' (the figure of the constellation); over time it came to mean 'of or relating to the constellation or zodiac sign Aquarius' and by extension 'a person born under or identifying with Aquarius'.