[n] the metabolic processes whereby certain organisms obtain energy from organic moelcules; processes that take place in the cells and tissues during which energy is released and carbon dioxide is produced and absorbed by the blood to be transported to the lungs
[n] the bodily process of inhalation and exhalation; the process of taking in oxygen from inhaled air and releasing carbon dioxide by exhalation
[n] a single complete act of breathing in and out; "thirty respirations per minute"