penny bank vs coin bank

penny bank and coin bank both are nouns.

Word	Noun	Adjective	Verb	Adverb
penny bank	Yes	No	No	No
coin bank	Yes	No	No	No

As nouns, coin bank is a hypernym of penny bank; that is, coin bank is a word with a broader meaning than penny bank:

penny bank: a child's coin bank (often shaped like a pig)
coin bank: a container (usually with a slot in the top) for keeping money at home

Other hypernyms of penny bank include bank, money box, savings bank.

penny bank (noun)	coin bank (noun)
a child's coin bank (often shaped like a pig)	a container (usually with a slot in the top) for keeping money at home