( US ) American English - Color ( UK ) British English - Colour

Seriously now, they are the same word spelled differently.

Colour is British. Color is American. There are a fair few words that the Americans drop the 'U' from. This is all thanks to Noah Webster. He came up with the American way of spelling things because he thought the English way was rubbish and to complicated. It's also thanks to him that words like 'centre' in English, is spelt 'center' in American.