The Collaborative International Dictionary of English v.0.48:

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.
   [1913 Webster]

WordNet (r) 3.0 (2006):

Calorie
    n 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 [syn:
         Calorie, kilogram calorie, kilocalorie, large
         calorie, nutritionist's calorie]
    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 [syn: calorie, gram
       calorie, small calorie]

Moby Thesaurus II by Grady Ward, 1.0:

20 Moby Thesaurus words for "calorie":
   BTU, British thermal unit, atomerg, dinamode, dyne, energid, erg,
   foot-pound, great calorie, horsepower-hour, horsepower-year, joule,
   kilocalorie, kilogram-meter, kilowatt-hour, photon, quantum,
   rational calorie, therm, thermal unit