sustaining pedal vs foot pedal

sustaining pedal and foot pedal both are nouns.

Word	Noun	Adjective	Verb	Adverb
sustaining pedal	Yes	No	No	No
foot pedal	Yes	No	No	No

As nouns, foot pedal is a hypernym of sustaining pedal; that is, foot pedal is a word with a broader meaning than sustaining pedal:

sustaining pedal: a pedal on a piano that lifts the dampers from the strings and so allows them to continue vibrating
foot pedal: a lever that is operated with the foot

Other hypernyms of sustaining pedal include foot lever, pedal, treadle.

sustaining pedal (noun)	foot pedal (noun)
a pedal on a piano that lifts the dampers from the strings and so allows them to continue vibrating	a lever that is operated with the foot