What is the meaning of Cuckold?

A man married to an unfaithful wife, especially when he is unaware or unaccepting of the fact.

A man who is paraphilically attracted to or aroused by the sexual infidelity of a partner.

A West Indian plectognath fish, Rhinesomus triqueter.

The scrawled cowfish, Acanthostracion quadricornis and allied species.

To make a cuckold or cuckquean of someone by being unfaithful, or by seducing their partner or spouse.

Source: wiktionary.org