REIT stands for a Real Estate Investment Trust. In the most simplistic definition, a REIT is to a real estate property as a mutual fund is to a stock. A large number of individuals pool their funds together, forming a REIT, and allow the REIT to purchase large real estate investments such as shopping malls, large apartment complexes, skyscrapers, or bulk amounts of single family homes. The REIT then distributes profits to its individual investors. This is one of the most hands-off approaches to investing in Real Estate, but do not expect the returns found in hands-on investing. You can buy shares in a REIT via your stock account. They often have a relatively high dividend payment.
Simply put…. REITs are an excellent way to invest in commercial real estate if you don’t want the headache of property management or just don’t have the money. I personally own the book "Investing in REITs" (right column). I recommend that you purchase this book to learn much more about REITs.