chord vs arpeggio

chord and arpeggio both are nouns.

Word	Noun	Adjective	Verb	Adverb
chord	Yes	No	Yes	No
arpeggio	Yes	No	No	No

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

chord: a combination of three or more notes that blend harmoniously when sounded together
arpeggio: a chord whose notes are played in rapid succession rather than simultaneously

Other hyponyms of chord include sforzando, common chord, triad, seventh chord.

chord (noun)	arpeggio (noun)
a combination of three or more notes that blend harmoniously when sounded together	a chord whose notes are played in rapid succession rather than simultaneously
a straight line connecting two points on a curve

chord (verb)	arpeggio (verb)
bring into consonance, harmony, or accord while making music or singing
play chords on (a stringed instrument)