| either of two lines of the color blue that are parallel to and equidistant from the goal lines and divide the rink into three zones of equal size. Also called zone line. Compare end zone (def. 2), neutral zone. |
blue·line or blue line  (blōō'līn')  n. Either of two blue lines running across an ice-hockey rink, usually 60 feet from each goal, and dividing the rink into defensive, neutral, and offensive zones. |
blue line n.
A bluish line along a border of the gums resulting from chronic lead poisoning.