The Collaborative International Dictionary of English v.0.48:

Checker \Check"er\ (ch[e^]k"[~e]r), n. [From Check, v. t.]
   One who checks.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Checker \Check"er\ (ch[e^]k"[~e]r), v. t. [imp. & p. p.
   Checkered (ch[e^]k"[~e]rd); p. pr. & vb. n. Checkering.]
   [From OF. eschequier a chessboard, F. ['e]chiquier. See
   Check, n., and cf. 3d Checker.]
   1. To mark with small squares like a checkerboard, as by
      crossing stripes of different colors.
      [1913 Webster]

   2. To variegate or diversify with different qualities,
      colors, scenes, or events; esp., to subject to frequent
      alternations of prosperity and adversity.
      [1913 Webster]

            Our minds are, as it were, checkered with truth and
            falsehood.                            --Addison.
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Checker \Check"er\, n. [OF. eschequier. See Checker, v. t.]
   1. A piece in the game of draughts or checkers.
      [1913 Webster]

   2. A pattern in checks; a single check.
      [1913 Webster]

   3. Checkerwork.
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   Note: This word is also written chequer.
         [1913 Webster]

WordNet (r) 3.0 (2006):

checker
    n 1: an attendant who checks coats or baggage
    2: one who checks the correctness of something
    3: one of the flat round pieces used in playing the game of
       checkers [syn: checker, chequer]
    v 1: mark into squares or draw squares on; draw crossed lines on
         [syn: check, checker, chequer]
    2: variegate with different colors, shades, or patterns [syn:
       checker, chequer]