The true freezing point of water. The temperature at which a mixture of air-saturated pure water and pure ice may exist in equilibrium at a pressure of one standard atmosphere.

The temperature at which a mixture of air-saturated pure water and pure ice may exist in equilibrium at a pressure of one standard atmosphere. The ice point is often used as one fiducial point (0°C or 32°F) in establishing a thermometric scale because it is reproduced relatively easily under laboratory conditions. The ice point is frequently called the freezing point, but the latter term should be reserved for the much broader reference to the solidification of any kind of liquid under various conditions. See melting point; compare boiling point.