power steering vs power-assisted steering

power steering and power-assisted steering both are nouns.

Word	Noun	Adjective	Verb	Adverb
power steering	Yes	No	No	No
power-assisted steering	Yes	No	No	No

As nouns, power steering and power-assisted steering are synonyms defined as:

power steering and power-assisted steering: automotive steering where engineer power amplifies the torque applied to the steering wheel

power steering (noun)	power-assisted steering (noun)
automotive steering where engineer power amplifies the torque applied to the steering wheel	automotive steering where engineer power amplifies the torque applied to the steering wheel