1. a nonmagnetic housing for a ship's compass (usually in front of the helm);
The Collaborative International Dictionary of English v.0.48:
Binnacle \Bin"na*cle\, n. [For bittacle, corrupted (perh. by
influence of bin) fr. Pg. bitacola binnacle, fr. L.
habitaculum dwelling place, fr. habitare to dwell. See
Habit, and cf. Bittacle.] (Naut.)
A case or box placed near the helmsman, containing the
compass of a ship, and a light to show it at night. --Totten.
WordNet (r) 3.0 (2006):
n 1: a nonmagnetic housing for a ship's compass (usually in
front of the helm)