auto/auth

self

Spelled auto, auth · autos 'self'

Greek autos meant self: an autobiography tells one's own life, autonomy grants self-rule, and an automatic device acts by itself.

Words built from it

automatic — operating by itself, without direct control
auto- (self) + -matic (acting)
autonomy — self-governance, independence
auto- (self) + -nomy (rule, law)
autobiography — an account of one's own life written by oneself
auto- (self) + bio (life) + -graphy (writing)
autonomous — self-governing, independent
auto- (self) + -nomous (self-governing)
authentic — genuine, of undisputed origin
auto- (self) + hent (doer) + -ic (relating to)
autocracy — government by one person with absolute power
auto- (self) + -cracy (rule)

authority — traces to Latin auctor 'author, originator' (from augere 'to increase'), not Greek autos 'self'