An SWF file is an animation created with Adobe Flash that can be played by Flash Player or with a web browser that has the Flash plugin installed. It may contain text, vector and raster graphics, and interactive content written in ActionScript.
SWF files are commonly used to bring animated graphics, video, and sound to the web. They are also a popular means of delivering browser-based games. Because SWF files contain compiled ActionScript and compressed media, they are not meant to be edited. To modify a Flash animation, it is recommended to edit the original .FLA file instead.
SWF (pronounced "Swiff") was originally an acronym for "Shockwave Flash" since the SWF format was designed for Shockwave Player. However, as SWF files became a standard means of publishing Flash content on the web, the acronym has been modified to mean Small Web Format as well.
NOTE: Flash was originally developed by Macromedia, which was acquired by Adobe Systems in 2005. Therefore, Macromedia Flash is now called Adobe Flash.