A cloak is a piece of clothing that covers your body, usually from the shoulders down. It's often worn for warmth or as part of a costume.
When we talk about cloaks, most people think of them as something to wear when it's cold outside - like a coat, but usually longer and more elaborate. We might imagine a wizard or a medieval knight wearing one in movies or books. But in real life, some people do still wear cloaks for fashion or as part of a uniform. For example, judges often wear black cloaks to court, which can be quite formal and impressive.
A long outer garment worn over the shoulders covering the back; a cape, often with a hood.
