USPTO definition:
A patent for an invention is the grant of a property right to the inventor, issued by the United States Patent and Trademark Office. . . . What is granted is not the right to make, use, offer for sale, sell or import, but the right to exclude others from making, using, offering for sale, selling or importing the invention.
The subject matter of a patent MUST be:
1. Useful,
2. Novel, &
3. Non-Obvious
General Information Concerning Patents from the USPTO.
PATENTABILITY--The patent statute sets forth three basic requirements or conditions for determining the patentability of a product or process--utility, novelty and nonobviousness. An applicant must be an original inventor (i.e., not have derived the subject matter from some other source) and must apply within one year of certain events that constitute potential statutory bars (e.g., public use). The Patent and Trademark Office determines the patentability of each claim during examination. After a patent issues, it is presumed valid. However, a party charged with infringement may contest the validity of any claim by showing noncompliance with the conditions of patentability.
1 Chisum on Patents GL1 (2019)
Utility Patent
USPTO definition:
"granted to anyone who invents or discovers any new and useful process, machine, article of manufacture, or compositions of matters, or any new useful improvement thereof"
E.g., US 4,787,847 (Sonicare®)
Design Patent
USPTO definition:
"granted to anyone who invents a new, original, and ornamental design for an article of manufacture"
Plant Patent
USPTO definition:
"granted to anyone who invents or discovers and asexually reproduces any distinct and new variety of plant"