An anomaly is a thing, a result, or sometimes a person that stands out because it is different from what is usual. The word names the odd thing itself, not the way it behaved. Scientists use it a lot: a number that does not sit on the line, a planet that does not move as the model says, a result nobody predicted. News writers like it too, because it sounds serious and a bit mysterious. In everyday talk, people more often say something strange or the odd one. People also stretch it: a very quiet child in a loud family might be called an anomaly, though that can feel a little cold, as if the person were a problem in the data. Though actually, an anomaly is not automatically a mistake. It is only something that does not match the pattern you brought with you. Sometimes the pattern is wrong, and the anomaly is the clue.