What is patent pending?

“Patent pending” simply means that someone has filed a patent application to protect some invention, but the United States Patent and Trademark Office has not yet made a determination of whether the invention meets the requirements to be entitled to a patent. By marking an invention with the phrase “patent pending,” the inventor is warning people that at some point in the future, a patent may be issued which will protect at least some aspect of the product and that copiers should be careful because they could end up infringing the inventor’s rights in the product. 

It should be noted that if someone places the phrase “patent pending” on a product when there is no related patent application filed with the PTO, they can be fined.