money box vs coin bank

money box and coin bank both are nouns.

Word	Noun	Adjective	Verb	Adverb
money box	Yes	No	No	No
coin bank	Yes	No	No	No

As nouns, money box and coin bank are synonyms defined as:

money box and coin bank: a container (usually with a slot in the top) for keeping money at home

Other synonyms of money box include bank, savings bank.

money box (noun)	coin bank (noun)
a strongbox for holding cash	a container (usually with a slot in the top) for keeping money at home
a container (usually with a slot in the top) for keeping money at home