WordNet sense 1 (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):

kilocalorie, kilogram calorie, large calorie, nutritionist's calorie

WordNet sense 2 (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):

gram calorie, small calorie