sextant

noun4

1. •
   A navigational device for deriving angular distances between objects so as to determine latitude and longitude.

   • I took our position every morning with my crude sextant; but the results were always most unsatisfactory. — 1918
2. •
   One sixth of a circle or disc; a sector with an angle of 60°.
3. •
   One of six groups of adjacent teeth, excluding the wisdom teeth.
4. •
   A radial cell division of segments in three series, a sixth part of the original.