n. 六分仪

Sextant \Sex"tant\, n. [L. sextans, -antis, the sixth part of an
as, fr. sextus sixth, sex six. See {Six}.]
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.

{Box sextant}, a small sextant inclosed in a cylindrical case
to make it more portable.