menstruum noun. ['mɛnstrʊǝm] Pl. -strua [-strʊǝ], -struums. LME.
[Latin, use as noun of menstruus monthly, from mensis month. In classical Latin (in sense 1) only as pl. menstrua.]
1. sing. & in pl. Menses. Now rare. LME.

2. Chemistry & Pharmacology. A solvent; a liquid medium. arch. E17.

► Sense 2 arose from alchemical analogy between the supposed agency of a solvent in the transmutation of metals and the supposed function of the menses in nurturing a developing foetus.

[TahlilGaran] English Dictionary ▲