Lewis Short
(P. a.) : ăquātus, a, um, as if from aquo, āre
* Mixed with water; hence, watery, thin: lac vernum aquatius aestivo,Plin. 28, 9, 33, § 124; so Sen. Q. N. 1, 3 fin.; Pall. 4, 1: vinum aquatissimum,Aug. Conf. 6, 2.—Adv.: ăquātē, with water, by the use of water; comp.: temperare aliquid aquatius,Plin. Val. 1, 10.—Sup.: aquatissime vinum temperare,Cael. Aur. Tard. 1, 4.
Charlton T. Lewis, Charles Short, A Latin Dictionary