west by north

American Heritage® Dictionary of the English Language, Fourth Edition

1. n. The direction or point on the mariner's compass halfway between due west and west-northwest, or 78°45ʹ west of due north.
2. adv. Toward or from west by north.

Wiktionary

1. n. The compass point halfway between west and west-northwest, specifically 281.25°, abbreviated as WbN.

GNU Webster's 1913

1. n. according to the notation of the mariner's compass, that point which lies 111/4° to the north or south, respectively, of the point due west.

WordNet 3.0

1. n. the compass point that is one point north of due west