RESPIRATION

noun Etymology: Middle English respiracioun, from Latin ~-, respiratio, from respirare Date: 15th century 1. the placing of air or dissolved gases in intimate contact with the circulating medium of a multicellular organism (as by breathing), a single complete act of breathing, the physical and chemical processes by which an organism supplies its cells and tissues with the oxygen needed for metabolism and relieves them of the carbon dioxide formed in energy-producing reactions, any of various energy-yielding oxidative reactions in living matter, respiratory adjective