tremor vs palpitation

tremor and palpitation both are nouns.

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

As nouns, palpitation is a hypernym of tremor; that is, palpitation is a word with a broader meaning than tremor:

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

Other hypernyms of tremor include quiver, quivering, shakiness, shaking, trembling, vibration.

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

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