12 letters · 14 points in Scrabble
noun the monthly discharge of blood from the uterus of nonpregnant women from puberty to menopause; ; --Hippocrates; --Aristotle
originFrom menstruum + -ation, modelled after Late Latin menstruatio. The word is a cognate with French menstruation, Spanish menstruación, which displaced Old English mōnaþblōd (literally “monthblood”).
Etymology from Wiktionary, CC BY-SA 3.0