Utility patents protect the functional characteristics of any machine, manufactured product, process or composition of matter. Most patents are of this type. Coverage begins with patent number D 242,583. Design patents protect the original ornamental design of manufactured products. Coverage begins with patent number PP 3,987.
Plant patents protect plants reproduced by methods other than seeds.
The U.S. Patent Office assigns subject classification codes to patents. You can search for patents on a particular subject area with this code. The Manual provides a hierarchical list of subjects by class and subclass. Also see Index search below. The Index is an alphabetical listing of subject headings.