The act of breathing out, or expelling air from the lungs.
The stage in respiration, or breathing, when air is expelled from the lungs. During this process, the diaphragm is pulled upward and the rib cage contracts, or moves downward.
The act of breathing out air from the lungs; exhalation.
Expulsion of air from the lungs in breathing. Normally the duration of expiration is shorter than that of inspiration. In general, if expiration lasts longer than inspiration, a pathological condition such as emphysema or asthma is present.