it is a science term, a kcal is equal to a common terminology calorie, but in science a kcal is really a 1000 smaller units of calorie, it is confusing, but even scientists use the term calorie to mean kcal
Yeah even though I've been told they are the same it does sound confusing, as kilo=thousand. So kcal literally would be 1000 cals correct? But when you see in cereal boxes, for 30g you get 300kcal. Obviously, that erases the doubt,....but still it's confusing.
If you want to be downright anal about things a calorie is a measure of heat...it's the quantity of heat required to raise 1 gram of water by 1 degree celcius at 1 atmosphere pressure
Now most people including myself just can't be bothered using the strict scientific definition so when people say that a meal has 500 calories (or that they burnt 500 calories during an hour of cardio) they really mean 500 000 calories or 500 kilocalories...