What does "pat. pend." mean?

The abbreviation "pat. pend." stands for "patent pending." This term means that the United States Patent and Trademark Office has a patent application on file for a particular item.

Manufacturers may only use the phrase "pat. pend." or "patent pending" if they have actually filed a patent application with the United States Patent and Trademark Office for that item. The law can impose a fine on anyone who uses these terms to imply that a patent application is pending when that is not actually the case. Patent applications are published 18 months after the application filing date. Until that time, or until the patent is issued, the details of the patent application are strictly confidential.