timekeeper vs measuring device

timekeeper and measuring device both are nouns.

Word	Noun	Adjective	Verb	Adverb
timekeeper	Yes	No	No	No
measuring device	Yes	No	No	No

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

timekeeper: a measuring instrument or device for keeping time
measuring device: instrument that shows the extent or amount or quantity or degree of something

Other hypernyms of timekeeper include measuring instrument, measuring system.

timekeeper (noun)	measuring device (noun)
a measuring instrument or device for keeping time	instrument that shows the extent or amount or quantity or degree of something
a clerk who keeps track of the hours worked by employees
(sports) an official who keeps track of the time elapsed