Plain English Meaning
It is the FAA's standard application paperwork a pilot fills out when they want a new certificate or rating, or to renew one. It lists who you are, what flying experience you have, and what you're applying for.
Full Definition
FAA Form 8710-1, titled 'Airman Certificate and/or Rating Application,' is the official application form used by pilots and other airmen to apply for a new pilot certificate, an additional rating on an existing certificate, or the renewal or reinstatement of a certificate. It records the applicant's personal information, aeronautical experience, instructor endorsements, and the type of certificate or rating sought, and is submitted to an FAA representative or Designated Pilot Examiner before a .