Glass

1. Something usually made of glass. A glass tabletop, a glass staircase, a glass window or door.
2. A drinking vessel. I need a glass for my water.
3. The contents of the vessel. He drank a glass of beer.
3. Plural, glasses. A pair of lenses usually made of glass or plastic, mounted in a light frame, used to correct faulty vision or to protect the eyes. She needed glasses to see. I wear dark glasses in the bright sunlight.