Sex meaning : A category into which sexually-reproducing organisms are divided on the basis of their reproductive roles in their species. Another category, especially of humans and especially based on sexuality or gender roles. The members of such a category, taken collectively. The distinction and relation between these categories, especially in humans; gender. (with "the") Women; the human female sex and those who belong to it. Sexual activity, usually sexual intercourse unless preceded by a modifier. Genitalia: a penis or vagina. To determine the sex of an animal. To have sex with.