sex

The English word 'sex' was borrowed directly from the Latin 'sexus' in the late 14th century. The origin of the Latin term is uncertain, but a prominent theory connects it to the verb 'secāre', meaning 'to cut, divide'. This etymological link suggests a fundamental concept of division, specifically the division of a species into two distinct categories. Over time, the meaning evolved from this abstract notion of a binary division to focus specifically on the division between male and female. By the late 19th century, its meaning extended to encompass the physical acts associated with this biological distinction.

The word is a simplex. It is a loanword from Latin where 'sexus' meant 'state of being male or female', 'the male or female division of a species'.