nub vs quintessence

nub and quintessence both are nouns.

Word	Noun	Adjective	Verb	Adverb
nub	Yes	No	No	No
quintessence	Yes	No	No	No

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

nub: the choicest or most essential or most vital part of some idea or experience
quintessence: the purest and most concentrated essence of something

Other hyponyms of nub include bare bones, hypostasis, haecceity, quiddity, stuff.

nub (noun)	quintessence (noun)
the choicest or most essential or most vital part of some idea or experience	the purest and most concentrated essence of something
a small piece	the most typical example or representative of a type
a small lump or protuberance	the fifth and highest element after air and earth and fire and water; was believed to be the substance composing all heavenly bodies