1) Aerobic 1) Metabolic process 2) Metabolism 3) Metastasis 4) Of breathing 5) Pertaining to respiration 6) Relating to breathing 
• (a.) Of or pertaining to respiration; serving for respiration; as, the respiratory organs; respiratory nerves; the respiratory function; respiratory changes.
(re- + L. spirare to breathe) pertaining to respiration.
[Adjective] Related to breathing or the lungs.
Having to do with respiration, the exchange of oxygen and carbon dioxide. From the Latin re- (again) + spirare (to breathe) = to breathe again.
To do with the processes of breathing and supplying the body with the oxygen it needs to survive, e.g., respiratory muscles are the muscles needed to breathe.
<physiology> Pertaining to respiration. ... Origin: L. Spirare = to breathe ... (18 Nov 1997) ... 
(res´pĭ-rә-tor″e) pertaining to respiration.
Relating to breathing.aids respiration / breathing
Re·spir'a·to·ry adjective (Physiol.) Of or pertaining to respiration; serving for respiration; as, the respiratory organs; respiratory nerves; the respiratory function; respiratory changes. Respiratory foods . (Physiol.) 
Type: Term Pronunciation: res′pi-ră-tōr′ē, rĕ-spīr′ă-tōr-ē Definitions: 1. Relating to respiration.
Respiratory: Having to do with respiration, the exchange of oxygen and carbon dioxide. From the Latin re- (again) + spirare (to breathe) = to breathe again.
[adj] - pertaining to respiration
breathing system
adjective pertaining to respiration; `respiratory assistance`