Final answer:
A **market maker** is an entity, individual, or institution that accepts the risk of holding a security in its own account to provide liquidity and facilitate trading.
Step-by-step explanation:
Any entity, individual or institution, willing to accept the risk of holding a particular security in its own account to facilitate trading and provide liquidity in that security is known as a **market maker**.
Market makers are important as they help ensure the smooth functioning of the financial markets by providing liquidity and facilitating trading. They do this by constantly quoting bid and ask prices for securities, thereby creating a market where buyers and sellers can trade with minimal delays and at fair prices. Examples of market makers include investment banks, brokerage firms, and specialized trading firms.