Lewis & Short

menstrŭus, a, um, adj. [mensis].

      1. 1. Of or belonging to a month, that happens every month, monthly.
    1. A. In gen. (class.): ferias menstruas edicere, Varr. L. L. 6, § 13 Müll.: usura, Cic. Att. 6, 1, 3: ventorum ratio, Plin. 2, 47, 48, § 128.
      1. 2. Subst.
          1. (α) menstrŭa, ōrum, n., the monthly sacri fices: ad menstrua solvenda montem ascendunt, Sall. Fragm. ap. Non. 492, 32.
          2. (β) menstrŭum, i, n.: menstruum meum Calend Septembr finitur, a monthly term of office, monthly service, Plin. Ep. 10, 24, 3.
    2. B. In partic., of or belonging to monthly purgations, to menstruation, menstruous: menstruae purgationes, Plin. 32, 10, 46, § 132: cursus, id. 11, 39, 94, § 230: sanguis, Vulg. Lev. 15, 25.
      As subst.: menstrŭa, ōrum, n., monthly purgations, menses, catamenia, Cels. 6, 6, 38: ciere, Plin. 22, 21, 30, § 65: sedare, id. 20, 14, 54, § 154.
      In sing., Plin. 28, 7, 23, § 78.
      Of female animals: canis, menstruous, Plin. 29, 5, 32, § 98.
  1. II. That lasts a month, for the space of a month, monthly: vita menstrua. Cic. Fin. 4, 12, 30: spatium, id. N. D. 1, 31, 87: menstrua cibaria. Cic. Verr. 2, 3, 30, § 72.
    As subst.: men-strŭum, i, n., a month’s provisions, Liv. 44, 2.