A liquid fund is a category of debt mutual fund that invests in very short-term instruments — typically maturing within 91 days — making it one of the safest and most stable types of mutual fund available. Because the underlying investments mature so quickly, liquid funds see minimal price fluctuation, and returns are usually modestly higher than a regular savings bank account.
Liquid funds are commonly used as a parking spot for surplus cash that you don't need immediately but might need on short notice — for instance, money waiting to be invested via an STP, an emergency fund, or funds set aside for an upcoming expense. Most liquid funds also offer an instant redemption facility for smaller amounts, crediting money to your bank account within minutes, making them almost as accessible as a savings account, but typically with better returns.