pendulum vs metronome

pendulum and metronome both are nouns.

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

As nouns, metronome is a hyponym of pendulum; that is, metronome is a word with a more specific, narrower meaning than pendulum:

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

Other hyponyms of pendulum include Foucault pendulum, compound pendulum, physical pendulum, simple pendulum.

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