Definition of menstruum in US English:


Pronunciation /ˈmenstrəwəm//ˈmenstrəm/

nounPlural menstrua

  • 1Menses.

    • ‘The viability of menstrual endometrial tissue in peritoneal fluid (PF) was evaluated and the morphologic changes in the mesothelial cells were studied by in vitro cocultures of menstruum with mesothelial cell monolayers.’
  • 2archaic A solvent.

    • ‘Through the menstrua gold does not acquire any other virtues than those it already has.’
    • ‘Let me say that again, there is an alchemical menstruum, that is completely plant based, which indeed can be made from any plant put through the alchemical process.’


Late Middle English (in menstruum (sense 1)): from Latin, neuter of menstruus ‘monthly’, from mensis ‘month’. menstruum (sense 2) is by analogy of the supposed agency of a solvent in the transmutation of metals into gold with the supposed action of menses on the ovum.