Calorie \Cal"o*rie\, n. [F., fr. L. calor heat.]

(Physics) The unit of heat according to the French standard; the amount of heat required to raise the temperature of one kilogram (sometimes, one gram) of water one degree centigrade, or from 0[deg] to 1[deg]. Compare the English standard unit, Foot pound.

Source: Webster's Revised Unabridged Dictionary (1913)