What is calorie?

calorie meaning in Enviromental Science terminology / glossary / dictionary is:
a basic measure of energy that has been replaced by the SI unit the joule; in physics it approximates the energy needed to increase the temperature of 1 gram of water by 1 °C which is about 4.184 joules. The Calories in food ratings (spelled with a capital C) and nutrition are ‘big C’ Calories or kcal.