Foucault pendulum vs pendulum

Foucault pendulum and pendulum both are nouns.

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

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

Foucault pendulum: pendulum with a long wire; can swing in any direction; the change in the swing plane demonstrates the earth's rotation
pendulum: an apparatus consisting of an object mounted so that it swings freely under the influence of gravity

Foucault pendulum (noun)	pendulum (noun)
pendulum with a long wire; can swing in any direction; the change in the swing plane demonstrates the earth's rotation	an apparatus consisting of an object mounted so that it swings freely under the influence of gravity