What is an abstract?
An abstract is "a short form of a speech, article, book, etc., giving only the most important facts or ideas" (Cambridge)
An abstract is a summary of a larger academic work.
The Five-Move Approach
In general, an abstract has five moves. A move is an aim. They are (1) background or situation, (2) aim of the paper or study, (3) method, (4) results, and (5) recommendations or implications.