A jacket is a piece of clothing worn over your other clothes, covering your arms and torso but stopping somewhere around your waist or hips. Jackets come in countless varieties: warm winter jackets filled with down feathers or synthetic insulation, lightweight rain jackets that keep you dry, denim jackets for casual wear, or dressy suit jackets for formal occasions.

Unlike coats, which are typically longer and heavier for cold weather, jackets are usually shorter and can serve many different purposes. You might wear a fleece jacket for a cool autumn evening, a windbreaker for bike riding, or a leather jacket just because you like how it looks. Some jackets zip up the front, others button up, and some pull over your head.

The word jacket can also refer to a protective covering for other things. A book's dust jacket is the removable paper cover that wraps around a hardcover book, often featuring colorful artwork and information about the story. The jacket of a baked potato is simply its skin. Life jackets keep swimmers afloat in water. In each case, the jacket serves as an outer layer that protects or covers what's inside.