apparent horizon vs skyline

apparent horizon and skyline both are nouns.

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

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

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

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

apparent horizon (noun)	skyline (noun)
the line at which the sky and Earth appear to meet	the line at which the sky and Earth appear to meet
	the outline of objects seen against the sky