n. /koh"stahr'/ ; v. /koh"stahr"/ , n. , v. , costarred, costarring .
n.
1. a performer, esp. an actor or actress, who shares star billing with another.
2. a performer whose status is slightly below that of a star.
v.i.
3. to share star billing with another performer.
4. to receive billing of slightly less status than that of a star.
v.t.
5. to present (two or more actors) as having equal billing or prominence.
6. to present as having slightly less status than that of a star.
Also, co-star .
[ 1915-20, Amer.; CO- + STAR ]