This is supercooling and it occurs with many substances, including water. Unless there is a nucleus for crystallization, you can cool water well below its melting point and it won't turn to ice (freeze). You can demonstrate this effect by cooling very pure water in a freezer in a smooth container to as low as −42 °C. Then if you disturb the water (shake it, pour it, or touch it), it will turn to ice as you watch. The freezing point of water and other liquids may be the same temperature as the melting point. It won't be higher, but it could easily be lower.