peace vs tranquillity

peace and tranquillity both are nouns.

Word	Noun	Adjective	Verb	Adverb
peace	Yes	No	No	No
tranquillity	Yes	No	No	No

As nouns, tranquillity is a hypernym of peace; that is, tranquillity is a word with a broader meaning than peace:

Other hypernyms of peace include quietness, quietude, tranquility.

peace (noun)	tranquillity (noun)
a treaty to cease hostilities	a disposition free from stress or emotion
the absence of mental stress or anxiety	a state of peace and quiet
the state prevailing during the absence of war	an untroubled state; free from disturbances
harmonious relations; freedom from disputes
the general security of public places