menstruum

noun

men·​stru·​um ˈmen(t)-strü-əm 

-strəm

plural menstruums or menstrua ˈmen(t)-strü-ə 

-strə

: a substance that dissolves a solid or holds it in suspension : solvent

Word History

Etymology

Medieval Latin, literally, menses, alteration of Latin menstrua

First Known Use

1559, in the meaning defined above

Medical Definition

menstruum

noun

men·​stru·​um ˈmen(t)-strə(-wə)m 

plural menstruums or menstrua -str(ə-w)ə 

: a substance that dissolves a solid or holds it in suspension : solvent