1.NounA non-SI unit of energy, equivalent to 4.184 kilojoules, that can raise the temperature of a kilogram of water by one degree Celsius. This is the unit normally used in food labeling.
2.NounA non-SI unit of energy, equivalent to 4.184 joules, that can raise the temperature of a gram of water by one degree Celsius. This unit was formerly widely used in chemistry and physics.