sights vs bombsight

sights and bombsight both are nouns.

Word	Noun	Adjective	Verb	Adverb
sights	Yes	No	No	No
bombsight	Yes	No	No	No

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

sights: an optical instrument for aiding the eye in aiming, as on a firearm or surveying instrument
bombsight: a sighting device in an aircraft for aiming bombs

Other hyponyms of sights include gun-sight, gunsight.

sights (noun)	bombsight (noun)
an optical instrument for aiding the eye in aiming, as on a firearm or surveying instrument	a sighting device in an aircraft for aiming bombs