sex-n; 2 Senses

Sense Number 1: The act of intercourse.

Commentary: SEX[+event]

They had sex in the back seat.
The film contained no sex or violence.
Great sex is the product of great communication.

PropBank: sex.01
WordNet 3.0 Sense Numbers: 1, 3

Sense Number 2: Either of the two categories (male or female) into which most organisms are divided, or key properties that distinguish the categories.

Commentary: SEX[+biological_category]

She didn't want to know the sex of the fetus.
There is a war between the sexes.
She showed him her sex.

PropBank: NM
WordNet 3.0 Sense Numbers: 2, 4