First of all, thanks to Wikipedia we see what Flash:

Adobe Flash is an application in the form of animation studio that works based on “frames” for the production and delivery of interactive content for different audiences around the world regardless of platform. It is currently written and distributed by Adobe, and uses vector graphics and raster images, sound, program code, stream video and bidirectional audio. Strictly speaking, Flash is the environment and Flash Player is the virtual machine used to execute files generated by Flash.

To learn a little more and put into practice, please visit FlashGuide tutorial that teaches us how to create a Flash animated text with a simple and ideal place to start.