Most states require real estate sales professionals to be licensed by the state, so that they can control education and experience requirements and have a central authority to resolve consumer problems.

The terminology used to identify real estate professionals varies a little from state to state.  Brokers are generally required to have more education and experience than real estate salespersons or agents.

The person you normally deal with is a real estate agent or salesperson.  The salesperson is licensed by the state, but must work for a broker.  All listings are placed in the broker's name, not the salesperson's.