dominoes

1. A tile divided into two squares, each having 0 to 6 (or sometimes more) dots or pips (as in dice), used in the game of dominoes.
2. A country that is expected to react to events in a neighboring country, according to the domino effect.
3. A masquerade costume consisting of a hooded robe and a mask covering the upper part of the face.
4. The mask itself.
5. The person wearing the costume.
6. A polyomino made up of two squares.
7. A mistake in performing.

noun

Any of several games played by arranging domino tiles on a flat surface.