Source : Webster's Revised Unabridged Dictionary (1913)

Menstrual \Men"stru*al\, a. [L. menstrualis: cf. F. menstruel.
   See {Menstruous}.]
   1. Recurring once a month; monthly; gone through in a month;
      as, the menstrual revolution of the moon; pertaining to
      monthly changes; as, the menstrual equation of the sun's
      place.

   2. Of or pertaining to the menses; as, menstrual discharges;
      the menstrual period.

   3. Of or pertaining to a menstruum. --Bacon.

Source : WordNet®

menstrual
     adj : of or relating to menstruation or the menses; "menstrual
           period" [syn: {catamenial}]