One of the four
phases of matter, a
liquid is a
fluid whose
volume is fixed under conditions of constant
temperature and
pressure and whose shape is usually determined by the container it fills. Liquids tend to pull themselves together into droplets due to
surface tension. The
kinetic energy in a liquid is greater than that of a solid, but less than that of a gas. Atoms in a liquid slide over one another, allowing the liquid to flow.
It should be noted that glass at normal temperatures is not a "supercooled liquid", but a solid. See the article on glass for more details.
See also gas, solid, plasma, ripple.
In linguistics, "liquid" can also refer to a liquid consonant.