Alchemy. = menstruum, n. 2a.

Originally: a solvent, esp. one for dissolving metal in the attempt to convert base metals into gold (now historical). Later also: a liquid used as a…

spec. A substance having the power to dissolve or disintegrate other substances; a solvent, a menstruum; †formerly, in Medicine, a substance…

A substance that dissolves another substance; a solvent: see dissolve, v. 2.

A substance (usually a liquid) having the power of dissolving other substances.

A dissolving agent; a solvent. Also figurative. Now rare.

A solvent.

A person or thing that dilutes; a diluent.

That which dilutes, dissolves, or makes more fluid; a diluting agent; a solvent.