orison vs prayer

orison and prayer both are nouns.

Word	Noun	Adjective	Verb	Adverb
orison	Yes	No	No	No
prayer	Yes	No	No	No

As nouns, orison and prayer are synonyms defined as:

Other synonyms of orison include petition.

orison (noun)	prayer (noun)
reverent petition to a deity	the act of communicating with a deity (especially as a petition or in adoration or contrition or thanksgiving)
	earnest or urgent request
	a fixed text used in praying
	reverent petition to a deity
	someone who prays to God