Meaning of "patent pending" and possibility of patenting first

Patent pending simply means that a patent application has been accepted by the patent office. The patent code requires an invention to be useful and novel (among other requirements) in order to obtain a patent. The useful requirement can be satisfied with a new and useful process, machine, manufacture, or composition of matter, or a new and useful improvement to a process, machine, manufacture, or composition of matter. The novel requirement is a bit more complicated, but your patent can be rejected (or later invalidated) if one of your competitors filed for a patent on the same invention first. If your competitor’s patent application is already published, you can discover their invention and determine if you have something that is different or improves the invention they disclosed. Otherwise, you are taking a chance that your invention will be viewed as different or an improvement over their disclosed technology. It is also important to take their product into account as well since products currently for sale also count as inventions prior to your patent application.