difference between “addressable” and “address” in memory?

I’m struggle on this practice question from this site….

Calculate the number of bits required in the address for memory having size of 16 GB. Assume the memory is 4-byte addressable.

MY QUESTION IS: what is the difference between an "address" and "the memory is 4 byte addressable"?

I understand an address would be its location in memory that is represented by bits, such as 2^n, where n is the number of bits in the address. But I’m confused about addressable in this question and how that’s different than address

2^n * 4 bytes = 2^34 The solution is 32 bits