Entry 2 senses · 2 variants Webster, 1913 Menstruate /mĕn'-stro͞o-ātˌ/ · Men·stru·ate · IPA /ˌmɛnstɹuˈeɪt/ a. v. i. 01 a. Menstruous. 1. Menstruous.[Obs.] 02 v. i. To discharge the menses; to have the catamenial flow. imp. & p. p. Menstruated; p. pr. & vb. n. Menstruating 1. To discharge the menses; to have the catamenial flow.