Definition of markers:
(n) :
Someone or something that creates marks, particularly
(n) :
A felt-tipped pen, a marker pen.
(n) :
A scorekeeper, especially one who tallies billiard scores.
(n) :
(paintball) A device that fires a paintball.
(n) :
Someone or something used to mark a position or amount, particularly
(n) :
A real or virtual objective, something to be aimed for.