men·stru·al (mĕnstr-əl) also men·stru·ous (-əs)
1. Of or relating to menstruation.
a. Taking place on a monthly basis.
b. Lasting for one month.
[Middle English, from Old French menstruel, from Latin mēnstruālis, from mēnstruus, menstrual, from mēnsis, month; see mē-2 in the Appendix of Indo-European roots.]
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