Provisional Patent Application
I'm often asked, "What is a provisional patent application?"
Well, when most folks imagine a patent, they imagine a utility patent. Essentially, utility patents protect useful, new and nonobvious products and processes.
In contrast, provisional patent applications don't issue as patents themselves, but instead function as priority documents. After filing a provisional patent application the Inventor has 1 year to file a regular utility patent application. A utility patent application can claim priority to a provisional patent application and therefore claim the benefit of its filing date when determining whether a reference predates the invention.
Provisional patent applications do not require many of the formalities found in a utility patent application and can therefore be less expensive. However a provisional patent application must still sufficiently disclose the invention to one skilled in the art.
You can find more information about the different types of patent applications at Biotech Beach Law's patent page.