Final answer:
A patent is a legal device that establishes property rights for an inventor, granting them exclusive rights for a set period and acting as a government-enforced barrier to entry.
Step-by-step explanation:
A patent is an example of a legal device for creating property rights. It is a government-issued grant that provides an inventor with the exclusive rights to manufacture, use, or sell their invention for a set number of years, acting as a government-enforced barrier to entry.
This ensures that the inventor can potentially recover the costs of research and development through commercial exploitation of the invention. A patent does not fit the definitions of a subsidy, pollution permit, voucher, or tax.