A patent is an intangible property right that gives the owner a limited monopoly on the claimed invention.
A patent confers the right to make, use, sell, offer for sale, advertise, import, export, or otherwise commercializing the claimed invention.
A patent can last from 15 to more than 20 years. This will depend on the type of patent granted and whether additional "stoppage time" in the form of patent-term adjustment is applied. Once the patent term expires, the invention is in the public domain and fair game for all.
There are three main types of patents: utility, design, and plant. A utility patent covers physical structures and functions, processes and methods, software, and formulae. A design patent covers the ornamental features of an object, simply the way something looks. A plant patent covers novel plant species that are asexually reproduced.
Some of you may be familiar with "provisional patents." This terminology is incorrect. There are provisional applications, not provisional patents. A provisional application is an informal utility patent application that acts more of like a placeholder, giving the applicant up to one year of patent-pending status before needing to cough up formal illustrations and claims based on the best version of the invention.
That's all the basics for now.