octant

English Thesaurus

1. a measuring instrument for measuring angles to a celestial body; similar to a sextant but with 45 degree calibration (noun.artifact)

hypernym	:	measuring device, measuring instrument, measuring system,
definition	:	instrument that shows the extent or amount or quantity or degree of something (noun.artifact)

part holonym	:	limb,
definition	:	the graduated arc that is attached to an instrument for measuring angles (noun.artifact)