What does patent pending mean?

In order to get a product on the market as quickly as possible, manufacturers sometimes use the phrase 'Patent pending' on products. This means that an application for a patent has been filed with the Patent and Trademark Office, but that the patent hasn't actually been granted. Patent protection doesn't begin until the patent is actually granted, so 'Patent pending' doesn't offer any specific protection by itself. It can, however, be used as proof that the idea for a product existed at a certain time. Use of this phrase when no application has been filed is illegal.