octant vs measuring instrument

octant and measuring instrument both are nouns.

Word	Noun	Adjective	Verb	Adverb
octant	Yes	No	No	No
measuring instrument	Yes	No	No	No

As nouns, measuring instrument is a hypernym of octant; that is, measuring instrument is a word with a broader meaning than octant:

octant: a measuring instrument for measuring angles to a celestial body; similar to a sextant but with 45 degree calibration
measuring instrument: instrument that shows the extent or amount or quantity or degree of something

Other hypernyms of octant include measuring device, measuring system.

octant (noun)	measuring instrument (noun)
a measuring instrument for measuring angles to a celestial body; similar to a sextant but with 45 degree calibration	instrument that shows the extent or amount or quantity or degree of something