Added 10 October 2026 menstruum /ˈmɛn.stɹʊəm/ noun Categories: NatureActionsObscure Words noun ! Definition from WordNet 3.1, Princeton University. Pronunciation from Wiktionary, via Kaikki.org. More about menstruum at Wordnik → Where our words come from → (archaic) a solvent. The monthly discharge of blood from the uterus of nonpregnant women from puberty to menopause. the women were sickly and subject to excessive menstruation Related Words: menstruemensesmenstrualmonthmenstruationfloodmonthscoursemenstrationmonthly Back to today's word