Patent: A grant made by a government that confers upon the creator of an invention the right to exclude others from making, using, selling, or importing that invention for a period of time.

Patent provides protection for up to twenty years from the earliest date of filing an application.  Patents typically cost several thousand U.S. dollars to prepare, for example: $7,500 for attorney fees for a simple mechanical patent, plus fees payable to the U.S. Patent Office.  When a patent expires, the invention goes to the public domain.

Effective January 17, 2015, the United States Patent and Trademark Office (USPTO) filing fees for a utility patent are $280; search fee of $600; and $720 examination fee.  The issue fee for a utility patent is $960.  Patent maintenance fees are $1,600 at 3.5 years after issue, $3,600 at 7.5 years and $7,400 at 11.5 years.  A small entity inventor pays reduced fees equal to one-half of many USPTO fees. A Micro Entity pays fees of one-half the small entity fees.