What is a provisional patent application?

A provisional application is an informal, yet complete, disclosure of an invention filed at the U.S. Patent and Trademark Office. It is never prosecuted by the Patent Office and does not, by itself, result in a patent. It buys the inventor (or his assignee) one year to decide whether or not to file a "regular" (a.k.a. "non-provisional" or "Utility") patent application. If the regular application is filed within that year, the regular application is accorded the same date as the provisional application.