stop payment vs purchase order

stop payment and purchase order both are nouns.

Word	Noun	Adjective	Verb	Adverb
stop payment	Yes	No	No	No
purchase order	Yes	No	No	No

As nouns, purchase order is a hypernym of stop payment; that is, purchase order is a word with a broader meaning than stop payment:

stop payment: a depositor's order to a bank to refuse payment on a check
purchase order: a commercial document used to request someone to supply something in return for payment and providing specifications and quantities

Other hypernyms of stop payment include order.

stop payment (noun)	purchase order (noun)
a depositor's order to a bank to refuse payment on a check	a commercial document used to request someone to supply something in return for payment and providing specifications and quantities