noun (plural kilocalories)

1. a non-SI unit of energy equal to 1,000 calories, used (now rare) in chemistry or physics; equal to 1 calorie or Calorie as used in nutrition. Symbol kcal.

Usage note: This prefix kilo- is generally applied to the small calorie, and not to the large calorie used in nutrition, to avoid confusion because 1,000 food calories would be 1,000,000 small calories.