Siding is the outer covering on the walls of a house or building that protects it from weather and gives it its finished look. When you look at most houses in your neighborhood, what you're seeing is the siding: it might be long horizontal boards of wood, vinyl panels that snap together, aluminum sheets, or even brick or stone.

Siding acts like a protective skin for a building. It keeps rain, snow, and wind from damaging the structure underneath, similar to how your own skin protects your body. Different materials work better in different climates: wood siding is traditional and beautiful but needs regular painting, while vinyl siding lasts longer with less maintenance. In very hot areas, lighter-colored siding can help keep houses cooler by reflecting sunlight.

When someone says they're re-siding their house, they're replacing the old outer covering with new material. This is a major home improvement project that can completely change how a building looks.