lookout vs observation tower

lookout and observation tower both are nouns.

Word	Noun	Adjective	Verb	Adverb
lookout	Yes	No	No	No
observation tower	Yes	No	No	No

As nouns, lookout and observation tower are synonyms defined as:

lookout and observation tower: a structure commanding a wide view of its surroundings

Other synonyms of lookout include lookout station, observatory.

lookout (noun)	observation tower (noun)
the act of looking out	a structure commanding a wide view of its surroundings
a structure commanding a wide view of its surroundings
an elevated post affording a wide view
a person employed to keep watch for some anticipated event