Final answer:
Angel investors are individuals who invest their own money into private companies for short-term financing in exchange for equity.
Step-by-step explanation:
Individuals who invest their own money in a private company to provide short-term financing are commonly known as angel investors. These investors typically have surplus funds and are looking for investment opportunities in small yet promising companies during their early stages of growth. In exchange for their investment, angel investors usually receive some ownership equity in the company, thereby becoming partial owners or shareholders of the firm. This investment not only provides the necessary capital for the business to develop but also can bring valuable business expertise and contacts from the investor.