Go to 'thermo-' entry Go to 'dino-' entry Go to 'chondro-' entry Go to 'aero-' entry Go to '-logy' entry Go to 'thaumato-' entry Go to 'nano-' entry Go to '-sophy' entry Go to 'bucco-' entry Go to '-ism' entry Go to '-lysis' entry Go to 'galacto-' entry Go to '-anthropy' entry Go to 'pneumo-' entry Go to '-ploitation' entry Go to '-lithic' entry Go to '-sepalous' entry Go to 'onco-' entry Go to '-parous' entry Go to 'dermato-' entry Go to 'multi-' entry Go to 'dodeca-' entry Go to '-zoon' entry Go to 'vermi-' entry Go to 'crystallo-' entry Go to 'biblio-' entry Go to 'eco-' entry Go to 'juxta-' entry Go to 'facio-' entry
Affixes: the building blocks of English
Affixes: the building blocks of English

exo-

External; from outside.

[Greek exō, outside.]

The great majority of words here are in modern technical and scientific usage; exceptions are exotic, which derives via Latin from Greek exōtikos, foreign, and exogamy (Greek gamos, marriage), the custom of marrying outside a community, clan, or tribe. Some examples of technical terms are exoskeleton, a rigid external covering for the body in some invertebrate animals; exothermic, of a chemical reaction or process that is accompanied by the release of heat; exogenous, developing from external factors; exobiology, the branch of science that deals with the possibility and likely nature of life on other planets or in space.

Its opposite is endo-; see also ecto-. Words such as exorbitant or exonerate instead contain Latin ex- (see ex-1); some, such as exodus or exorcize, come from Greek (see ex-2).

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