Above and On

Above adjective - Appearing earlier in the same text.

On is a synonym for above in on top of topic. In some cases you can use "On" instead the word "Above" as a preposition or an adjective.

On adjective - Being in effective operation.

Above is a synonym for on in position topic. You can use "Above" instead the word "On" as an adverb or an adjective, if it concerns topics such as ahead of.