Simple Definition:
A broker is a person or a company that helps people buy or sell things (such as stocks, houses, or insurance). Brokers work as the middleman between buyers and sellers, helping them find each other and complete the transaction. For example, a stockbroker helps investors buy or sell stocks, and a real estate broker helps people buy or sell houses.
Very Simple Definition:
A broker is someone who helps people buy or sell things. For example, a stockbroker helps people buy or sell stocks, and a real estate broker helps people buy or sell houses.