A tile is a flat piece of material that's used to cover a roof, floor, or wall. If you're artistic, you can make a mosaic out of small, colorful glass tiles.
Most tiles are made out of ceramic, metal, glass, or stone. Many baths and showers are lined with ceramic tiles, and it's also common to find tiles covering bathroom and kitchen floors. Historians have traced tiles back at least as far as the 13th century BCE, in Mesopotamia. To cover a surface in tiles is to tile. Flat, hard game pieces are also commonly known as tiles, like the Scrabble tiles you pick at the beginning of a game. The root of this word means "to cover."