A window is an opening in a wall, door, roof, or vehicle that allows the exchange of light and may also allow the passage of sound and sometimes air. Modern windows are usually glazed or covered in some other transparent or translucent material, a sash set in a frame in the opening; the sash and frame are also referred to as a window. Many glazed windows may be opened, to allow ventilation, or closed, to exclude inclement weather. Windows may have a latch or similar mechanism to lock the window shut or to hold it open by various amounts.
Alabaster "mullion"-divided decorative windows in Santa Maria La Major church (Morella, Spain)
Alabaster window in the Valencia Cathedral. Note the asymmetrical, slanted left side of the wall-frame, which lets sun rays reach the chancel
Ancient Egyptian sandstone window grill from a palace of Ramesses III, now in the Metropolitan Museum of Art (New York City)
Fragment of a Roman window glass plate dated to 1st to 4th century CE. Note the obvious curvature; this is not a flat pane
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
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)
Wall art in Budapest's Széll Kálmán Square.
Glass curtain walls on a contemporary German skyscraper
Mirrored glass partition wall
Demountable wall and door in an office building