Pronunciation: (pôr"tl-ä'nō, pōr"-), [key]
—pl. -nos, -niPronunciation: (-nē). [key]
a descriptive atlas of the Middle Ages, giving sailing directions and providing charts showing rhumb lines and the location of ports and various coastal features. Also called rutter.
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.