A regularly-shaped slab of clay or other material, affixed to cover or decorate a surface, as in a roof-tile, glazed tile, stove tile, carpet tile, etc.

(computing) A rectangular graphic.

Any of various flat cuboid playing pieces used in certain games, such as dominoes, Scrabble, or mahjong.

(transitive) To cover with tiles.

(graphical user interface) To arrange in a regular pattern, with adjoining edges (applied to tile-like objects, graphics, windows in a computer interface).

(computing theory) To optimize (a loop in program code) by means of the tiling technique.

(Freemasonry) To seal a lodge against intrusions from unauthorised people.

To protect from the intrusion of the uninitiated.