sextant vs measuring instrument

sextant and measuring instrument both are nouns.

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

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

sextant: a measuring instrument for measuring the angular distance between celestial objects; resembles an octant
measuring instrument: instrument that shows the extent or amount or quantity or degree of something

Other hypernyms of sextant include measuring device, measuring system.

sextant (noun)	measuring instrument (noun)
a measuring instrument for measuring the angular distance between celestial objects; resembles an octant	instrument that shows the extent or amount or quantity or degree of something
a unit of angular distance equal to 60 degrees