c. 1600, "the art of beautifying, art of anointing or decorating the human body," from Latinized form of Greek kosmetike (tekhnē) "the art of dress and ornament," from fem. of kosmetikos "skilled in adornment or arrangement," from kosmein "to arrange, adorn," from kosmos "order; ornament" (see cosmos). The adjective is feminine because tekhne is a feminine noun.
Meaning "a preparation for beautifying, preparation that renders the n soft and pure or improves the complexion" (originally also the hair) is attested from 1640s. Related: Cosmetics.