A patent is a document issued by a national government. It grants an inventor the right to prevent anyone else from making, using or selling his or her invention without permission. In most countries, the right lasts twenty years.
In exchange, the inventor must provide a detailed description of the invention. This allows others to benefit from knowledge about current technologies, while maintaining the inventors' right to profit from it.
A Canadian patent only grants rights within Canada. Inventors who wish to extend their rights to other countries must apply for patents in those countries (however, there is a streamlined process for this; see the International Patent Cooperation Treaty section). A group of patents from different countries, protecting a single invention, is called a patent family.