What they areEdit
These are entities that specialize in some aspect of the real estate industry. REIT's are different in that the profits are not taxed at the corporate level. To maintain that status, at least 90% of annual net income has to be paid out in dividends.
For purposes of the United State tax code, these dividends are not qualified for special tax treatment.
Most REIT's focus on owning some specific type of real estate. It might be residential like apartments or hotels. Or it might be commercial like offices or mall. There is on REIT that specializes in owning hospitals that are leased back to the doctors that run them.
Other REIT's deal with real estate financing such as mortgages.