palpitation vs tremor

palpitation and tremor both are nouns.

Word	Noun	Adjective	Verb	Adverb
palpitation	Yes	No	No	No
tremor	Yes	No	Yes	No

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

palpitation: a shaky motion
tremor: shaking or trembling (usually resulting from weakness or stress or disease)

Other hyponyms of palpitation include tremolo.

palpitation (noun)	tremor (noun)
a rapid and irregular heart beat	an involuntary vibration (as if from illness or fear)
a shaky motion	a small earthquake
	shaking or trembling (usually resulting from weakness or stress or disease)

palpitation (verb)	tremor (verb)
	shake with seismic vibrations