DuckCorp Dico

Found one definition

1.                 From The Collaborative International Dictionary of English v.0.48:
                   
   
   
                   
                     
   Marker \Mark"er\, n.
      One who or that which marks. Specifically:
      (a) One who keeps account of a game played, as of billiards.
      (b) A counter used in card playing and other games.
      (c) (Mil.) The soldier who forms the pilot of a wheeling
          column, or marks the direction of an alignment.
      (d) An attachment to a sewing machine for marking a line on
          the fabric by creasing it.
          [1913 Webster]