mate

A checkmate.

To checkmate or achieve a checkmate.

One of a matched pair.

A spouse or romantic partner.

Either of a pair of birds or other animals that associate in order to propagate.

Either of a pair of animals brought together for breeding.

Either of a pair of plants, fungi, or other organisms that engage in sexual reproduction or conjugation with each other.

A person with whom one is in close association; an associate.