Above and Ahead

Above adverb - To or in a higher place.

Ahead and above are semantically related in already topic. In some cases you can use "Ahead" instead an adverb "Above", when it comes to topics like sooner.

Ahead adverb - So as to precede something in order of time.

Above and ahead are semantically related in already topic. Sometimes you can use "Above" instead an adverb "Ahead", if it concerns topics such as sooner.