apparent horizon vs horizon

apparent horizon and horizon both are nouns.

Word	Noun	Adjective	Verb	Adverb
apparent horizon	Yes	No	No	No
horizon	Yes	No	No	No

As nouns, apparent horizon and horizon are synonyms defined as:

apparent horizon and horizon: the line at which the sky and Earth appear to meet

Other synonyms of apparent horizon include sensible horizon, skyline, visible horizon.

apparent horizon (noun)	horizon (noun)
the line at which the sky and Earth appear to meet	the range of interest or activity that can be anticipated
	the line at which the sky and Earth appear to meet
	a specific layer or stratum of soil or subsoil in a vertical cross section of land
	the great circle on the celestial sphere whose plane passes through the sensible horizon and the center of the Earth