a card, sheet, or the like, with two compass roses printed on it concentrically, for recording, on a given voyage, the amount of deviation for which the navigator must compensate in using the ship's compass to steer a magnetic course.
COMPASS DEVIATION CARD
Meaning of COMPASS DEVIATION CARD in English
Random House Webster's Unabridged English dictionary. Полный английский словарь Вебстер - Random House . 2012