Nolo's Plain-English Law Dictionary

Utility Patent

The most common type of patent; issued for useful inventions that are new (novel) and that produce results that are not expected by those working in the field of invention (nonobvious). A utility patent lasts for 20 years from the patent application's filing date. (See also: patent, novelty, nonobviousness)
NOLO-web4:DRU1.6.12.2.20161011.41205