respiration

Concise Oxford English Dictionary © 2008 Oxford University Press:
respiration/respəˈreɪʃn/

▶noun

• 1 the action of breathing.

  ■ a single breath.

• 2 Biology the processes in living organisms involving the production of energy, typically with the intake of oxygen and the release of carbon dioxide, from the oxidation of organic substances.

– origin ME: from L. respiratio(n-), from respirare (see respire).