autobus vs bus

autobus and bus both are nouns.

Word	Noun	Adjective	Verb	Adverb
autobus	Yes	No	No	No
bus	Yes	No	Yes	No

As nouns, autobus and bus are synonyms defined as:

autobus and bus: a vehicle carrying many passengers; used for public transport

Other synonyms of autobus include charabanc, coach, double-decker, jitney, motorbus, motorcoach, omnibus, passenger vehicle.

autobus (noun)	bus (noun)
a vehicle carrying many passengers; used for public transport	a vehicle carrying many passengers; used for public transport
	a car that is old and unreliable
	an electrical conductor that makes a common connection between several circuits
	the topology of a network whose components are connected by a busbar

autobus (verb)	bus (verb)
	remove used dishes from the table in restaurants
	ride in a bus
	send or move around by bus