A wall is a structure and a surface that defines an area; carries a load; provides security, shelter, or soundproofing; or, is decorative. There are many kinds of walls, including:

• Walls in buildings that form a fundamental part of the superstructure or separate interior rooms, sometimes for fire safety
• Glass walls (a wall in which the primary structure is made of glass; does not include openings within walls that have glass coverings: these are windows)
• Border barriers between countries
• Brick walls
• Defensive walls in fortifications
• Permanent, solid fences
• Retaining walls, which hold back dirt, stone, water, or noise sound
• Stone walls
• Walls that protect from oceans (seawalls) or rivers (levees)