solid propellant rocket vs solid-propellant motor

solid propellant rocket and solid-propellant motor both are nouns.

Word	Noun	Adjective	Verb	Adverb
solid propellant rocket	Yes	No	No	No
solid-propellant motor	Yes	No	No	No

As nouns, solid propellant rocket and solid-propellant motor are synonyms defined as:

solid propellant rocket and solid-propellant motor: A chemical rocket engine which uses propellant in a solid state.

Other synonyms of solid propellant rocket include solid-fuel rocket.

solid propellant rocket (noun)	solid-propellant motor (noun)
A chemical rocket engine which uses propellant in a solid state.	A chemical rocket engine which uses propellant in a solid state.