A U.S. patent is a legal right granted by the United States Patent and Trademark Office (USPTO) that gives an inventor exclusive rights to their invention. This means that the inventor has the right to prevent others from making, using, selling, and importing the invention within the United States for a limited period, usually 20 years from the filing date of the patent application. In exchange for this protection, the inventor must publicly disclose the details of the invention in a patent application. A patent application is a detailed written description of an invention’s structure and function, accompanied by mandatory patent-quality drawings. A patent application has often been described by the courts as the most difficult legal document to draft because it must be written pursuant to strict regulations so as to result in a patent that is valid and enforceable.

There are three main types of U.S. patents:
1. Utility Patents: These protect new and useful processes, machines, articles of manufacture, or compositions of matter (or improvements to existing ones). This is the most common type of patent.

2. Design Patents: These protect new, original, and ornamental designs for articles of manufacture. Unlike utility patents, they focus on the appearance of an object, not its function.
3. Plant Patents: These protect new and distinct varieties of plants that are asexually reproduced (e.g., through grafting rather than from seed).

A valid patent cannot be granted for an invention that was patented or described in a printed publication in this or a foreign country or in public use or on sale in this country more than one year prior to the date of the application for patent in the United States. A valid patent application may only be filed in the name of the actual inventor or inventors of the invention over which patent protection is sought. In addition, patent protection is generally unavailable in countries other than the United States if the invention is publicly used or otherwise disclosed anywhere in the world before a patent application is filed.