A US patent is a property right granted by the US government to all of the actual, first inventor(s) of an invention under the US constitution and statues passed by Congress that grants the inventors the right to exclude others from making, using, selling, or importing the invention for a specific period of time. It does not grant the right to make, use, sell, or import the invention to the patent holder(s) since patents can overlap and end up being mutually exclusive (e.g. where a first patented product uses a second patented product as part of the first patented product the first patent could not be utilized without the second patent holder's permission).
There are three types of patents: A utility patent is the type most inventors obtain for their invention and it can be issued for a:
Article of manufacture
Composition of matter
Improvements of any of the above
A design patent can issue only for a specific ornamental design and cannot be used to protect a functional element.
A plant patent can issue for a sexually reproduced plant.