Meaning

• A rampart of earth, stones etc. built up for defensive purposes.

• A structure built for defense surrounding a city, castle etc.

  "The town wall was surrounded by a moat."

• Each of the substantial structures acting either as the exterior of or divisions within a structure.

  "We're adding another wall in this room during the remodeling.  The wind blew against the walls of the tent."

• A point of desperation.

• A point of defeat or extinction.

• An impediment to free movement.

  "A wall of police officers met the protesters before they reached the capitol steps."

• A type of butterfly (Lasiommata megera).

• (often in combination) A barrier.

  "a seawall;  a firewall"

• A barrier to vision.

• Something with the apparent solidity and dimensions of a building wall.

  "a wall of sound;  a wall of water"

• A divisive or containing structure in an organ or cavity.

• (auction) A fictional bidder used to increase the price at an auction.

• A doctor who tries to admit as few patients as possible.

• A line of defenders set up between an opposing free-kick taker and the goal.

• A personal notice board listing messages of interest to a particular user.

Meaning

• To enclose with, or as if with, a wall or walls.

  "He walled the study with books."