relating to or produced by or consisting of volcanoes; "volcanic steam"; "volcanic islands such as Iceland"; "a volcanic cone is a conical mountain or hill built up of material from volcanic eruptions"
2.
explosively unstable; "a volcanic temper"
3.
igneous rock produced by eruption and solidified on or near the earth's surface; rhyolite or andesite or basalt; "volcanic rock includes the volcanic glass obsidian"
A"que*ous\, a. [Cf. F. aqueux, L. aquosus, fr. aqua. See Aqua, Aquose.]1. Partaking of the nature of water, or abounding with it; watery. The aqueous vapor of the air. --Tyndall. 2. Made from, or by means of, water. An aqueous deposit. --Dana. Aqueous extract, an extract obtained from a vegetable substance by steeping it in water. Aqueous humor (Anat.), one the humors of the eye; a limpid fluid, occupying the space between the crystalline lens and the cornea. (See Eye.) Aqueous rocks (Geol.), those which are deposited from water and lie in strata, as opposed to volcanic rocks, which are of igneous origin; -- called also sedimentary rocks.