RAREFACTION

rarefaction. Rarefaction, n. expansion of the parts of a body

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Rar′e‐fac″tion (răr′ē̍‐făk″shŭn), n. [[Cf. F. raréfaction. See Rarefy.]] The act or process of rarefying; the state of being rarefied; — opposed to condensation; as, the rarefaction of air.