One of the spaces in different parts of the bodies of birds, which are filled with air and connected with the air passages of the lungs; an air cell.
Webster's Revised Unabridged Dictionary
| APA | Webster's. (2011). air sac. Retrieved September 28, 2026, from http://smartdefine.org/air_sac/definitions/1971984 |
| Chicago | Webster's. 2011. "air sac" http://smartdefine.org/air_sac/definitions/1971984 (accessed September 28, 2026). |
| Harvard | Webster's 2011, air sac, Smart Define, viewed 28 September, 2026, <http://smartdefine.org/air_sac/definitions/1971984>. |
| MLA | Webster's. "air sac" 27 May 2011. Web. 28 September 2026. <http://smartdefine.org/air_sac/definitions/1971984> |