reciprocating engine vs plunger

reciprocating engine and plunger both are nouns.

Word	Noun	Adjective	Verb	Adverb
reciprocating engine	Yes	No	No	No
plunger	Yes	No	No	No

reciprocating engine (noun)	plunger (noun)
an internal-combustion engine in which the crankshaft is turned by pistons moving up and down in cylinders	mechanical device that has a plunging or thrusting motion
	hand tool consisting of a stick with a rubber suction cup at one end; used to clean clogged drains
	someone who risks losses for the possibility of considerable gains
	someone who dives (into water)