letter of mark and reprisal vs letter of marque

letter of mark and reprisal and letter of marque both are nouns.

Word	Noun	Adjective	Verb	Adverb
letter of mark and reprisal	Yes	No	No	No
letter of marque	Yes	No	No	No

As nouns, letter of mark and reprisal and letter of marque are synonyms defined as:

letter of mark and reprisal and letter of marque: a license to a private citizen to seize vessels of another nation and their property

Other synonyms of letter of mark and reprisal include letters of marque.

letter of mark and reprisal (noun)	letter of marque (noun)
a license to a private citizen to seize vessels of another nation and their property	a license to a private citizen to seize vessels of another nation and their property