The Collaborative International Dictionary
Menstruums
Menstruum \Men"stru*um\, n.; pl. E. Menstruums, L. Menstrua. Any substance which dissolves a solid body; a solvent.
The proper menstruum to dissolve metal.
--Bacon.
All liquors are called menstruums which are used as
dissolvents, or to extract the virtues of ingredients
by infusion or decoction.
--Quincy.
Note: The use is supposed to have originated in some notion
of the old chemists about the influence of the moon in
the preparation of dissolvents.
--Johnson.
Wiktionary
menstruums
n. (plural of menstruum English)