plunger vs mechanical device

plunger and mechanical device both are nouns.

Word	Noun	Adjective	Verb	Adverb
plunger	Yes	No	No	No
mechanical device	Yes	No	No	No

As nouns, mechanical device is a hypernym of plunger; that is, mechanical device is a word with a broader meaning than plunger:

plunger: mechanical device that has a plunging or thrusting motion
mechanical device: mechanism consisting of a device that works on mechanical principles

plunger (noun)	mechanical device (noun)
mechanical device that has a plunging or thrusting motion	mechanism consisting of a device that works on mechanical principles
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)