sex
A category into which sexually-reproducing organisms are divided on the basis of their reproductive roles in their species; the system of such categories, which can differ by organism or by taxonomic branch.
Example
“The effect of the medication is dependent upon age, sex, and other factors.”
Other meanings
Another category, especially of humans and especially based on sexuality or gender roles.
The members of such a category, taken collectively.
Word history
From Latin "sexus" (gender; gender traits; males or females; genitals).
Where this comes from
This definition is adapted from “sex” on Wiktionary, by its contributors, published under CC BY-SA 4.0. This page is published under the same licence.