menses

n. menstruation, woman's monthly cycle (Physiology)

The menstrual cycle is a recurring cycle of physiologic changes that occurs in the females of several mammals, including human beings and other apes. Humans are the only species that has a menstrual cycle with concealed ovulation. Other placental mammals experience an estrus, or heat, where imminent ovulation is signaled to the males of the species.
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Menses /men·ses/ the monthly flow of blood from the female genital tract. men·ses n. The monthly flow of blood and cellular debris from the uterus [more]Menses - Community and Resources

Noun
1. the monthly discharge of blood from the uterus of nonpregnant women from puberty to menopause; "the women were sickly and subject to excessive menstruation"; "a woman does not take the gout unless her menses be stopped"--Hippocrates; "the semen begins to appear in males and to be emitted at the same time of life that the catamenia begin to flow in females"--Aristotle
(synonym) menstruation, menstruum, catamenia, period, flow
(hypernym) discharge, emission, expelling
(hyponym) menorrhagia, hypermenorrhea

(n. pl.)
The catamenial or menstrual discharge, a periodic flow of blood or bloody fluid from the uterus or female generative organs.