Investor is the entity who makes investments. Investing involves using money to make money. In the business world, investors consist of many different entities that will put money into a business in hopes that it will succeed and repay their initial investment plus the rate of return that was agreed upon when the investment was made. In public markets, investors consist of stock holders as well as bond holders.
The public can invest in a company through the purchase of shares of ownership (stock) or lending money with the expectation that they will get the full amount back plus interest (bonds.) Other types of investors include institutional investors which are large organizations that invest their own assets in a company or assets from others that are held in a trust.
These organizations include insurance companies, hedge funds, banks, mutual funds, and other investment companies.