The term 'A Glass or Type of Pigeon' can be summarized as a TUMBLER, which is a seven-letter word. Tumblers are a breed of fancy pigeon that are bred to perform acrobatic stunts in the air. They are characterized by their ability to fly in a series of somersaults and twists, and they are often used in competitions. The breed was developed in Europe in the 19th century and is now popular around the world.