costar

As nouns the difference between costard and costar

is that costard is (british) a large cooking apple while costar is (acting) a person who shares star billing.

As a verb costar is

to perform with the billing of a costar.

Costar is a related term of costa.

As nouns the difference between costa and costar

is that costa is a rib while costar is a person who shares star billing.

As a verb costar is

to perform with the billing of a costar.

As nouns the difference between costar and cohost

is that costar is a person who shares star billing while cohost is a joint host alongside another (compare costar).

As verbs the difference between costar and cohost

is that costar is to perform with the billing of a costar while cohost is to act as a joint host.