1. Definition

Tiles are roofing elements laid on an inclined plane, with an overlap to ensure watertightness.

The term "tile" generally refers to roofing products, originally all made from clay, but nowadays also made from concrete. But the word "tile" remains imprecise in its meaning, as we also speak of glass tiles, metal tiles and even solar tiles. So it's not so much the composition as the function that defines a tile.