(Oct. 1, 2019) Quartermaster 3rd Class Zachary Gladstone reads a surface contact bearing using a telescopic alidade on the starboard bridge-wing of the amphibious transport dock ship USS Green Bay (LPD-20) during an anchorage evolution. (U.S. Navy photo by Mass Communication Specialist 2nd Class Anaid Banuelos Rodriguez)

Definition

Noun

  • An instrument for taking bearings to an object.

Origin

15th century. Via Middle English and Latin, from the Arabic word alhidadah, for turning radius.

Comments

A fairly standard piece of equipment and useful for obtaining a visual fix.

References

Rogers, J.G. (1985). Origins of Sea Terms. Mystic Seaport.