wall

An upright structure of masonry, wood, plaster, or other building material serving to enclose, divide, or protect an area, especially a vertical construction forming an inner partition or exterior siding of a building.

A continuous structure of masonry or other material forming a rampart and built for defensive purposes.

A structure of stonework, cement, or other material built to retain a flow of water.

Something resembling a wall in appearance, function, or construction, as the exterior surface of a body organ or part.

Something resembling a wall in impenetrability or strength.

An extreme or desperate condition or position, such as defeat or ruin.

The vertical surface of an ocean wave in surfing.

To enclose, surround, or fortify with or as if with a wall: synonym: enclose.

To divide or separate with or as if with a wall. Often used with off: