One word can often mean different things. But what about one word that also means its exact opposite? Words like this are called contronyms, or "auto-antonyms." Perhaps one of the most famous examples is cleave, which means both to split apart and to stick together. Another example is trim, which can mean to put something on (think "trim the tree"), or to take something off. We've collected some awesome videos on this topic. Watch them now to learn more.