metronome vs pendulum

metronome and pendulum both are nouns.

Word	Noun	Adjective	Verb	Adverb
metronome	Yes	No	No	No
pendulum	Yes	No	No	No

As nouns, pendulum is a hypernym of metronome; that is, pendulum is a word with a broader meaning than metronome:

metronome: clicking pendulum indicates the exact tempo of a piece of music
pendulum: an apparatus consisting of an object mounted so that it swings freely under the influence of gravity

metronome (noun)	pendulum (noun)
clicking pendulum indicates the exact tempo of a piece of music	an apparatus consisting of an object mounted so that it swings freely under the influence of gravity