Humour or humor (see spelling differences) is the tendency of particular images, stories or situations to provoke laughter and provide amusement. Many theories exist about what humour is and what social function it serves. Yet, people of all ages and cultures respond to humour and most people share a common sense of humour. The term derives from the humoral medicine of the ancient Greeks, which stated that a mix of fluids known as humours (Greek: χυμός, chymos… (More on Humorous)