1. Also called gram Calorie, small Calorie

2. A unit equal to one gram calorie per square centimeter of irradiated surface measure solar radiation.

3. Definition of Calorie 1 a : the amount of heat required at a pressure of one atmosphere to raise the temperature of one gram of water one degree Celsius that is equal to about 4.19 joules —abbreviation cal — called also gram Calorie, small Calorie