Junk, any of various Chinese sailing vessels, used in the Far East for thousands of years. Junks are wooden craft, up to 30 by 10 ft (9 by 3 m), with flat-bottoms, high sterns (rears) and square bows (fronts). They have tall, heavy masts, up to 5 in number, with sails made of cotton cloth or straw matting. They have deep rudders and little or no keel. Though some people live on junks, they are now mainly used for transporting goods on rivers and coastal waters.