aque·ous \ˈākwēəs, ˈak-\adjective Etymology: Medieval Latin aqueus, from Latin aqua + -eus -eous 1. a.: of, relating to, or having the characteristics of water : watery < the aqueous vapor of the air — John Tyndall > b.: made from, with, or by means of water < aqueous solutions > c.: produced by the action of water < aqueous deposits > 2.: of or relating to the aqueous humor • aque·ous·lyadverb