pocket money vs pin money

pocket money and pin money both are nouns.

Word	Noun	Adjective	Verb	Adverb
pocket money	Yes	No	No	No
pin money	Yes	No	No	No

As nouns, pocket money and pin money are synonyms defined as:

pocket money and pin money: cash for day-to-day spending on incidental expenses

Other synonyms of pocket money include spending money.

pocket money (noun)	pin money (noun)
cash for day-to-day spending on incidental expenses	cash for day-to-day spending on incidental expenses