What is the difference between a bank and a credit union?

A credit union shares its profits with clients.

To expand on what @RedDeerGuy1 said, credit unions are non-profit and do not have to pay taxes. To open an account or get a loan, you need to become a member. The members are considered to be the owners as well as customers of the credit union. The interest you receive on your deposit is like the dividend that you get from owning stocks. There are no outside shareholders.