1. a unit of energy or heat; the amount of energy needed to raise the temperature of one gram of water by one degree Celsius (also called small calorie or gram calorie)
Usage: scientific/technical term; often abbreviated as 'cal'; distinct from kilocalorie (kcal), which is commonly called a 'Calorie' in nutrition
2. a unit of energy in food; a kilocalorie (1,000 small calories), commonly used in nutrition and diet contexts
Usage: informal usage in everyday contexts; technically a kilocalorie, but often called 'calorie' in popular speech; capitalized as 'Calorie' in formal scientific writing to distinguish from small calorie

Examples

• One calory of heat will raise the temperature of one gram of water by one degree Celsius.
• A typical apple contains about 95 calories.
• The food label shows that this snack has 150 calories per serving.
• Athletes often track their calory intake to maintain their energy levels.
• Burning 3,500 calories is roughly equivalent to losing one pound of body weight.
• The calory content of different foods varies widely depending on their composition.