sextant Meaning, Definition & Usage

  1. noun a unit of angular distance equal to 60 degrees
  2. noun a measuring instrument for measuring the angular distance between celestial objects; resembles an octant

WordNet

Sex"tant noun
Etymology
L. sextans, -antis, the sixth part of an as, fr. sextus sixth, sex six. See Six.
Definitions
  1. (Math.) The sixth part of a circle.
  2. An instrument for measuring angular distances between objects, -- used esp. at sea, for ascertaining the latitude and longitude. It is constructed on the same optical principle as Hadley's quadrant, but usually of metal, with a nicer graduation, telescopic sight, and its arc the sixth, and sometimes the third, part of a circle. See Quadrant.
  3. (Astron.) The constellation Sextans.

Webster 1913