A wall is a vertical structure that defines and encloses a space, providing separation, support, and sometimes insulation, protection, or aesthetic elements. Walls can serve various functions:

1. Load-Bearing Walls: These walls support the weight of floors and the roof above, distributing the load down to the foundation. They are essential to a building's structural integrity.
2. Non-Load-Bearing Walls: These walls, also called partition walls, primarily divide spaces and do not support any structural weight other than their own. They are often used to create rooms and define spaces within a building.
3. Exterior Walls: These walls form the outer enclosure of a building, providing security, insulation from weather, and aesthetic value. They may be built from materials such as brick, concrete, or glass.
4. Interior Walls: These are inside the building, dividing rooms or sections. They can be load-bearing or non-load-bearing, depending on the building's structure.

Walls are built using various materials, including brick, stone, concrete, wood, metal, or even glass. They can include openings like doors and windows, which contribute to a building's function and design.