c.1600, "delicately woven cotton fabric," from French mousseline (17c.), from Italian mussolina, from Mussolo, Italian name of Mosul, city in northern Mesopotamia (modern Iraq) where muslin was made. Like many fabric names, it has changed meaning over the years, in this case from luxurious to commonplace. In 13c. French, mosulin meant "cloth of silk and gold." The meaning "everyday cotton fabric for shirts, bedding, etc." is first attested 1872 in American English.