Source : Webster's Revised Unabridged Dictionary (1913)

Domino \Dom"i*no\, n.; pl. {Dominos} or (esp. the pieces for a
   game) {Dominoes}. [F. domino, or It. domin[`o], or Sp.
   domin['o], fr. L. dominus master. The domino was orig. a hood
   worn by the canons of a cathedral. See {Don}, {Dame}.]
   1. A kind of hood worn by the canons of a cathedral church; a
      sort of amice. --Kersey.

   2. A mourning veil formerly worn by women.

   3. A kind of mask; particularly, a half mask worn at
      masquerades, to conceal the upper part of the face.
      Dominos were formerly worn by ladies in traveling.

   4. A costume worn as a disguise at masquerades, consisting of
      a robe with a hood adjustable at pleasure.

   5. A person wearing a domino.

   6. pl. A game played by two or more persons, with
      twenty-eight pieces of wood, bone, or ivory, of a flat,
      oblong shape, plain at the back, but on the face divided
      by a line in the middle, and either left blank or
      variously dotted after the manner of dice. The game is
      played by matching the spots or the blank of an unmatched
      half of a domino already played --Hoyle.

   7. One of the pieces with which the game of dominoes is
      played. --Hoyle.

Source : WordNet®

dominos
     n : any of several games played with small rectangular blocks
         [syn: {dominoes}]