wall
noun(wall)
an embankment built around a space for defensive purposes
Examples:
They blew the trumpet and the walls came tumbling down. 
wall
noun(wall)
(anatomy) a layer (a lining or membrane) that encloses a structure
Examples:
Stomach walls. 
wall
verb(wall)
surround with a wall in order to fortify
wall
noun(wall)
a difficult or awkward situation
Examples:
His back was to the wall. 
Competition was pushing them to the wall. 
wall
noun(wall)
a layer of material that encloses space
Examples:
The walls of the cylinder were perforated. 
The container's walls were blue. 
wall
noun(wall)
a masonry fence (as around an estate or garden)
Examples:
The wall followed the road. 
He ducked behind the garden wall and waited. 
wall
noun(wall)
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. 
wall
noun(wall)
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. 
wall
noun(wall)
a vertical (or almost vertical) smooth rock face (as of a cave or mountain)