[res-puh-rey-shuh n]


the act of respiring; inhalation and exhalation of air; breathing.
  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.

Origin of respiration

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
Related formsres·pi·ra·tion·al, adjectivepre·res·pi·ra·tion, noun Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

Related Words for respiration

process, exhalation, inhalation

Examples from the Web for respiration

Contemporary Examples of respiration

Historical Examples of respiration

  • And moderation, as it was justly said once, is the respiration of the philosopher.

    The Book of Khalid

    Ameen Rihani

  • In the first instance it served only as an organ of respiration.

    The Meaning of Evolution

    Samuel Christian Schmucker

  • He was thinner than before, and his eyes were red and his respiration difficult.

    The Christian

    Hall Caine

  • It only hurries the respiration, and chokes the pulmonary vessels.

  • Jimmy's respiration was so rapid that it couldn't be counted, so faint that it couldn't be heard.

British Dictionary definitions for respiration



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
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)
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Word Origin and History for respiration

late 14c., from Latin respirationem (nominative respiratio) "breathing, respiration," noun of action from past participle stem of respirare (see respire).

Online Etymology Dictionary, © 2010 Douglas Harper

respiration in Medicine




The act or process of inhaling and exhaling; breathing.ventilation
The act or process by which an organism without lungs, such as a fish or plant, exchanges gases with its environment.
The oxidative process occurring within living cells by which the chemical energy of organic molecules is released in a series of metabolic steps involving the consumption of oxygen and the liberation of carbon dioxide and water.
Any of various analogous metabolic processes by which organisms, such as fungi, obtain energy from organic molecules.
The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.

respiration in Science



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.
See cellular respiration.
The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

respiration in Culture


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


Carbon dioxide is a waste product of respiration.
The New Dictionary of Cultural Literacy, Third Edition Copyright © 2005 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.