Meaning of blue line

blue' line"

Pronunciation: [key]
— Ice Hockey. Ice Hockey.
  1. 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 calledCf. end zone (def. 2),

blue•line

Pronunciation: (bl'līn"), [key]
— n. Print.
  1. a print made on light-sensitive paper and used as a proof for checking the position of stripped-up negatives or positives and copy prior to platemaking.
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.