metrical foot vs metre

metrical foot and metre both are nouns.

Word	Noun	Adjective	Verb	Adverb
metrical foot	Yes	No	No	No
metre	Yes	No	No	No

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

metrical foot: (prosody) a group of 2 or 3 syllables forming the basic unit of poetic rhythm
metre: (prosody) the accent in a metrical foot of verse

Other hypernyms of metrical foot include beat, cadence, measure, meter.

metrical foot (noun)	metre (noun)
(prosody) a group of 2 or 3 syllables forming the basic unit of poetic rhythm	rhythm as given by division into parts of equal duration
	(prosody) the accent in a metrical foot of verse
	the basic unit of length adopted under the Systeme International d'Unites (approximately 1.094 yards)