faint constellation and 11th zodiac sign, late Old English, from Latin aquarius, literally "water carrier," properly an adjective, "pertaining to water" (see aquarium); a loan-translation of Greek Hydrokhoos "the water-pourer," old Greek name of this constellation.
Aquarians were a former Christian sect that used water instead of wine at the Lord's Supper. Age of Aquarius (1940) is an astrological epoch supposed to have begun in the 1960s, embodying the traits of this sign and characterized by world peace and human brotherhood. The term and the concept probably got a boost in popular use when An Aquarian Exposition was used as the sub-name of the Woodstock Music & Art Fair (1969).
