petition vs request

petition and request both are nouns.

Word	Noun	Adjective	Verb	Adverb
petition	Yes	No	Yes	No
request	Yes	No	Yes	No

As nouns, petition and request are synonyms defined as:

petition and request: a formal message requesting something that is submitted to an authority

Other synonyms of petition include postulation.

As nouns, request is a hypernym of petition; that is, request is a word with a broader meaning than petition:

Other hypernyms of petition include asking.

As verbs, request is a hypernym of petition; that is, request is a word with a broader meaning than petition:

petition: write a petition for something to somebody; request formally and in writing
request: express the need or desire for

Other hypernyms of petition include ask for, bespeak, call for, quest.

petition (noun)	request (noun)
a formal message requesting something that is submitted to an authority	the verbal act of requesting
reverent petition to a deity	a formal message requesting something that is submitted to an authority

petition (verb)	request (verb)
write a petition for something to somebody; request formally and in writing	express the need or desire for
	ask (a person) to do something
	inquire for (information)