Meaning of OCTANT in English

OCTANT

[oc.tant] n [L octant-, octans eighth of a circle, fr. octo] (1731) 1: an instrument for observing altitudes of a celestial body from a moving ship or aircraft

2: any of the eight parts into which a space is divided by three coordinate planes

Merriam-Webster English vocab.      Английский словарь Merriam Webster.