A patent is a type of intellectual property. It is a document that describes an invention and grants the holder the exclusive right to manufacture the invention in the country that granted the patent for a limited amount of time. In order for an invention to be granted a patent, it must be:
You could request a patent for a process, machine, article of manufacture, composition of matter, or an improvement to any of these things, but there are some things that cannot be patented, such as:
For more information, UWaterloo's Office of Research - Waterloo Commercialization Office has Information about Intellectual Property describing what a patent is and what is and isn't patentable. The Canadian Intellectual Property Office has a useful A Guide to Patents on the web.
Patents have their own structure and terminology, so if you've never seen one before it can be daunting. Visuals and descriptions of a patent are available through Pennsylvania State University Library's document: