1) Breath 
• (a.) Pertaining to, or employed in, the expiration or emission of air from the lungs; as, the expiratory muscles.
Ex·pir'a·to·ry adjective (Physiol.) Pertaining to, or employed in, the expiration or emission of air from the lungs; as, the expiratory muscles. 
Type: Term Pronunciation: ek-spī′ră-tō-rē Definitions: 1. Relating to expiration.
[adj] - relating to the breathing out phase of respiration
adjective of or relating to the breathing out phase of respiration
pertaining to the expiration of air from the lungs.