what is patent term

Is the ownership of a patent for the whole life of the patent? No, the patent is granted for a specified period. After expiry of the period, the patent expires, the protection ends, and an invention enters the public domain. After expiry of the period granted, the patent is open and the invention can be commercially exploited by anyone without infringing the patent. Patent term varies from country to country, usually it is 20 years. There are many factors with which patent term changes so roughly it is  20 years but it varies based on term extensions, terminal disclaimer etc.