men ‧ stru ‧ ate /ˈmenstrueɪt/ BrE AmE verb [intransitive]
[ Date: 1800-1900 ; Language: Late Latin ; Origin: past participle of menstruari , from Latin menstruus 'monthly' , from mensis 'month' ]
when a woman menstruates, usually every month, blood flows from her body
—menstruation /ˌmenstruˈeɪʃ ə n/ noun [uncountable]