The abstract is a summary of the disclosure as a whole in a single paragraph of 250 words or less. In that the most widely-available patent searching software is capable of searching for patent titles and abstracts by key words and phrases, care should be taken to ensure that appropriate key words and phrases occur in patent abstracts. It should fulfill the purpose of permitting the patent office and the public to rapidly determine the nature and gist of the technical disclosure from a cursory inspection.
MPEP 608.01(a) - Arrangement of Application MPEP 608.01(b) - Abstract of the Disclosure
Law - Abstract of the Disclosure