quivering vs tremolo

quivering and tremolo both are nouns.

Word	Noun	Adjective	Verb	Adverb
quivering	Yes	No	No	No
tremolo	Yes	No	No	No

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

quivering: a shaky motion
tremolo: (music) a tremulous effect produced by rapid repetition of a single tone or rapid alternation of two tones

Other hyponyms of quivering include tremor.

quivering (noun)	tremolo (noun)
the act of vibrating	vocal vibrato especially an excessive or poorly controlled one
a shaky motion	(music) a tremulous effect produced by rapid repetition of a single tone or rapid alternation of two tones