rotary engine vs radial engine

rotary engine and radial engine both are nouns.

Word	Noun	Adjective	Verb	Adverb
rotary engine	Yes	No	No	No
radial engine	Yes	No	No	No

As nouns, rotary engine and radial engine are synonyms defined as:

rotary engine and radial engine: an internal-combustion engine having cylinders arranged radially around a central crankcase

rotary engine (noun)	radial engine (noun)
an internal-combustion engine in which power is transmitted directly to rotating components	an internal-combustion engine having cylinders arranged radially around a central crankcase
an internal-combustion engine having cylinders arranged radially around a central crankcase