respiration

[ res-puh-rey-shuhn ]

noun

1. the act of respiring; inhalation and exhalation of air; breathing.
2. Biology.
   1. the sum total of the physical and chemical processes in an organism by which oxygen is conveyed to tissues and cells, and the oxidation products, carbon dioxide and water, are given off.
   2. an analogous chemical process, as in muscle cells or in anaerobic bacteria, occurring in the absence of oxygen.

respiration

/ ˌrɛspəˈreɪʃən /

noun

1. the process in living organisms of taking in oxygen from the surroundings and giving out carbon dioxide ( external respiration ). In terrestrial animals this is effected by breathing air
2. the chemical breakdown of complex organic substances, such as carbohydrates and fats, that takes place in the cells and tissues of animals and plants, during which energy is released and carbon dioxide produced ( internal respiration )

respiration

/ rĕs′pə-rā′shən /

1. The process by which organisms exchange gases, especially oxygen and carbon dioxide, with the environment. In air-breathing vertebrates, respiration takes place in the lungs. In fish and many invertebrates, respiration takes place through the gills. Respiration in green plants occurs during photosynthesis.
2. See cellular respiration

respiration

1. The conversion of oxygen by living things into the energy by which they continue life. Respiration is part of metabolism .

Notes

Carbon dioxide is a waste product of respiration.

Other Words From

• respi·ration·al adjective
• preres·pi·ration noun

Word History and Origins

Origin of respiration¹

1400–50; late Middle English respiracioun < Latin respīrātiōn- (stem of respīrātiō ) a breathing out, equivalent to respīrāt ( us ) (past participle of respīrāre to respire ) + -iōn- -ion