menstruate UK /ˈmɛnstɹʊeɪt/US /ˌmɛnstɹuˈeɪt/verb 2adjective 1forms 3 verb2 •To undergo menstruation, to have a period.A woman may have every quality or attribute of marriageableness who menstruates irregularly, or rarely, or even who has never menstruated at all. — 1884 •(no longer used, rare) To stain with or as if with menses. adjective1 •(no longer used) Menstrual. formsmenstruated · menstruating · menstruates