A liquid is a fluid. Unlike a solid, the molecules in a liquid have a much greater freedom to move. The forces that bind the molecules together in a solid are only temporary in a liquid, allowing a liquid to flow while a solid remains rigid. A liquid, like a gas, displays the properties of a fluid.

In addition to drinks and other fluids, most cosmetics and a variety of foods are considered liquid. For example moisturisers, toothpastes, mascaras, aerosols, gels, canned fruit, fish and meat, frozen foods, butter, cream cheeses and yoghurts are treated as liquids.