Money-market funds, also known as money-market mutual funds, are open-ended mutual funds that invest in short-term debt securities. There are several synonyms for the term "money-market funds." For instance, these funds can be referred to as cash-equivalent funds, as they invest in highly liquid assets that are considered to be similar to cash. Another term used to describe money-market funds is treasury bills funds, as they frequently include U.S. Treasury funds (T-bills) among their holdings. Some may also refer to these funds as short-term bond funds, as they invest in fixed-income securities with short durations. Overall, money-market funds serve as a popular investment choice for investors who prioritize liquidity and stability over higher yields.