What is Patent Prosecution?

Legal Definition
Patent prosecution describes the interaction between applicants and their representatives, and a patent office with regard to a patent, or an application for a patent. Broadly, patent prosecution can be split into pre-grant prosecution, which involves negotiation with a patent office for the grant of a patent, and post-grant prosecution, which involves issues such as post-grant amendment and opposition.

Patent prosecution is distinct from patent litigation, which describes legal action relating to the infringement of patents.

The rules and laws governing patent prosecution are often laid out in manuals released by the Patent Offices of various governments, such as the Manual of Patent Examining Procedure (MPEP) in the United States, or the Manual of Patent Office Practice (MOPOP) in Canada.
-- Wikipedia
Legal Definition
General name for the process of obtaining a patent and defending its validity if challenged via reexamination. At the core of a patent prosecution is the interaction between an applicant and the Patent and Trademark Office. The applicant is usually represented by an attorney.