the menses; menstrual flow or a menstrual period
Origin of menstruationMedieval Latin menstruatio
The monthly flow of blood and cellular debris from the uterus that begins at puberty in women and the females of certain other primates. In women, menstruation ceases at menopause. Also called catamenia, menses.
(countable and uncountable, plural menstruations)
menstrual +"Ž -ation