tachymeter vs theodolite

tachymeter and theodolite both are nouns.

Word	Noun	Adjective	Verb	Adverb
tachymeter	Yes	No	No	No
theodolite	Yes	No	No	No

As nouns, theodolite is a hypernym of tachymeter; that is, theodolite is a word with a broader meaning than tachymeter:

tachymeter: a theodolite designed for rapid measurements
theodolite: a surveying instrument for measuring horizontal and vertical angles, consisting of a small telescope mounted on a tripod

Other hypernyms of tachymeter include transit.

tachymeter (noun)	theodolite (noun)
a theodolite designed for rapid measurements	a surveying instrument for measuring horizontal and vertical angles, consisting of a small telescope mounted on a tripod