[n. koh-stahr; v. koh-stahr] 
noun, verb, -starred, -star⋅ring.| 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. |
| 3. | to share star billing with another performer. |
| 4. | to receive billing of slightly less status than that of a star. |
| 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. |
| co·star also co-star (kō'stär') n. A starring actor or actress given equal status with another or others in a play or film. tr. & intr.v. co·starred also co-starred, co·star·ring also co-star·ring, co·stars also co-stars To act or present as a costar. |
