A launch is a type of motor boat e.g. a pilot launch.
To launch, is to hurl forward, set in motion or make a start. Traditionally when a ship was launched, it would be sent speeding down a ramp into the water. Nowadays they're more usually floated out, a safer and more sedate process, which is still referred to as launching the vessel.
In the case of a book launch, the word means to introduce a new product. My latest book was launched just two weeks ago.
Have you launched anything lately, or perhaps you're planning on launching in the near future?