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.
If a liquid is at rest in a uniform gravitational field, the pressure at any point is given by
where is the density of the liquid (assumed constant) and is the depth of the point below the surface. Note that this formula assumes that the pressure at the free surface is zero.
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.