calorie

(noun) a unit of heat equal to the amount of heat required to raise the temperature of one kilogram of water by one degree at one atmosphere pressure; used by nutritionists to characterize the energy-producing potential in food. Synonyms: Calorie, kilogram calorie, kilocalorie, large calorie, nutritionist's calorie.

(noun) unit of heat defined as the quantity of heat required to raise the temperature of 1 gram of water by 1 degree centigrade at atmospheric pressure. Synonyms: gram calorie, small calorie.