Definitions:

1. A protective covering or casing around an object. NOUN
   • Phonograph records were sold in cardboard jackets.
   • The wires were encased in a durable plastic jacket to prevent damage.
2. An outer garment extending either to the waist or the hips, typically having sleeves and a fastening down the front. NOUN
   • She chose to wear a blue jacket with white stripes.
   • You will need to wear a jacket, because it is below freezing outside.
3. In chemistry, can refer to a vessel or container that surrounds another vessel, usually for the purpose of controlling temperature during a chemical reaction or process. NOUN
   • The reaction flask was placed inside a jacketed vessel to control the temperature.
4. In dentistry, a dental appliance consisting of an artificial crown for a broken or decayed tooth. NOUN
   • I got a new jacket last week and my tooth feels so much better.
5. Refers to a metal covering or casing, typically made of copper or another alloy, that surrounds a bullet. NOUN
   • The bullet's copper jacket helped it maintain stability and accuracy during flight.
6. The outer skin of a potato. NOUN
   • Wash the jackets before you boil the potatoes.
7. The paper cover that wraps around a hardcover book. NOUN
   • The book's jacket featured an intricate illustration that captured the essence of the story.

Synonyms:

• cap
• capsule
• case
• casing
• coat
• cover
• crown
• housing
• sheath