astronomy vs astrometry

astronomy and astrometry both are nouns.

Word	Noun	Adjective	Verb	Adverb
astronomy	Yes	No	No	No
astrometry	Yes	No	No	No

As nouns, astrometry is a hyponym of astronomy; that is, astrometry is a word with a more specific, narrower meaning than astronomy:

astronomy: the branch of physics that studies celestial bodies and the universe as a whole
astrometry: the branch of astronomy that deals with the measurement of the position and motion of celestial bodies

astronomy (noun)	astrometry (noun)
the branch of physics that studies celestial bodies and the universe as a whole	the branch of astronomy that deals with the measurement of the position and motion of celestial bodies