instance vs precedent

instance and precedent both are nouns.

Word	Noun	Adjective	Verb	Adverb
instance	Yes	No	Yes	No
precedent	Yes	Yes	No	No

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

instance: an item of information that is typical of a class or group
precedent: an example that is used to justify similar occurrences at a later time

Other hyponyms of instance include apology, excuse, exception, case in point, quintessence, sample, specimen.

instance (noun)	precedent (noun)
an item of information that is typical of a class or group	an example that is used to justify similar occurrences at a later time
an occurrence of something	(civil law) a law established by following earlier judicial decisions
	a subject mentioned earlier (preceding in time)
	a system of jurisprudence based on judicial precedents rather than statutory laws

instance (adjective)	precedent (adjective)
	preceding in time, order, or significance

instance (verb)	precedent (verb)
clarify by giving an example of