exo/ecto

outside, external

Spelled exo, ecto · exo 'outside'

Greek exo meant outside: an exoskeleton sits outside, an exoplanet circles another star, and exogenous forces come from beyond a system.

Words built from it

exotic — originating from a foreign, unfamiliar place
exo- (outside) + -tic (relating to)
exodus — a mass departure of people
exo- (out) + hod (way)
exoskeleton — a hard external supporting structure of an animal
exo- (outside) + skeleton (dried body)
exoplanet — a planet outside our solar system
exo- (outside) + planet
exogenous — originating from outside a system
exo- (outside) + gen (produced)
ectothermic — relying on external heat to regulate body temperature
ecto- (outside) + therm (heat)

exorbitant — from Latin ex- 'out of' + orbita 'wheel track, orbit' — a Latin ex-, not the Greek exo- root here