What's the difference between i.e. and e.g.?
"water," late 14c.; see aqua-. Used in late Middle English in combinations to mean "decoction, solution" (cf. aqua regia, a mix of concentrated acids, literally "royal water," so called for its power to dissolve gold and other "noble" metals). As the name of a light greenish-blue color, 1936.
word-forming element meaning "water," from Latin aqua "water; the sea; rain," cognate with Proto-Germanic *akhwo, source of Old English ea "river," Gothic ahua "river, waters," Old Norse Ægir, name of the sea-god, Old English ieg "island;" all from PIE *akwa- "water" (cf. Sanskrit ap "water," Hittite akwanzi "they drink," Lithuanian uppe "a river").