In chemistry, to be dissolved in water. Denoted by putting the subscript (aq) after the chemical symbol. For instance, salt disassociating in water to form sodium and chlorine ions:

NaCl(s) --> Na+(aq) + Cl-(aq)

All acids and alkali are defined as being aqueous. So we don't say "aqueous hydrogen chloride". Instead we say "hydrochloric acid".

A"que*ous (#), a. [Cf. F. aqueux, L. aquosus, fr. aqua. See Aqua, Aquose.]


Partaking of the nature of water, or abounding with it; watery.

The aqueous vapor of the air. Tyndall.


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.


© Webster 1913.

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