wall

(noun) an architectural partition with a height and length greater than its thickness; used to divide or enclose an area or to support another structure. Examples: "The south wall had a small window." "The walls were covered with pictures."

(noun) anything that suggests a wall in structure or function or effect. Examples: "A wall of water." "A wall of smoke." "A wall of prejudice." "Negotiations ran into a brick wall."

(noun) (anatomy) a layer (a lining or membrane) that encloses a structure. Synonyms: paries. Example: "Stomach walls."

(noun) a difficult or awkward situation. Examples: "His back was to the wall." "Competition was pushing them to the wall."

(noun) a vertical (or almost vertical) smooth rock face (as of a cave or mountain).

(noun) a layer of material that encloses space. Examples: "The walls of the cylinder were perforated." "The container's walls were blue."

(noun) a masonry fence (as around an estate or garden). Examples: "The wall followed the road." "He ducked behind the garden wall and waited."

(noun) an embankment built around a space for defensive purposes. Synonyms: rampart, bulwark. Examples: "They stormed the ramparts of the city." "They blew the trumpet and the walls came tumbling down."

(verb) surround with a wall in order to fortify. Synonyms: palisade, fence, fence in, surround.