Flash is a set of multimedia software. Flash has become a popular method for adding animation and interactivity to web pages; Flash is commonly used to create animation, advertisements, and various web page components, to integrate video into web pages, and more recently, to develop rich Internet applications.

Flash can manipulate vector and raster graphics and supports bi-directional streaming of audio and video. It contains a scripting language called ActionScript. Several software products, systems, and devices are able to create or display Flash content, including Flash Player, which is available for most common web browsers, some mobile phones and other electronic devices (using Flash Lite). The Flash Professional multimedia authoring program is used to create content for the Engagement Platform, such as web applications, games and movies, and content for mobile phones and other embedded devices.

Files in the SWF format, traditionally called "ShockWave Flash" movies, "Flash movies" or "Flash games", usually have a .swf file extension and may be an object of a web page, strictly "played" in a standalone Flash Player, or incorporated into a Projector, a self-executing Flash movie (with the .exe extension in Microsoft Windows). Flash Video (FLV) files have a .flv file extension and are either used from within .swf files or played through a flv aware player, such as VLC, or QuickTime and Windows Media Player with external codecs added.