invitation vs request

invitation and request both are nouns.

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

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

invitation: a request (spoken or written) to participate or be present or take part in something
request: the verbal act of requesting

Other hypernyms of invitation include letter, missive, asking.

invitation (noun)	request (noun)
a tempting allurement	the verbal act of requesting
a request (spoken or written) to participate or be present or take part in something	a formal message requesting something that is submitted to an authority

invitation (verb)	request (verb)
	express the need or desire for
	ask (a person) to do something
	inquire for (information)