MRAID
MRAID or ‘Mobile Rich Media Ad Interface Definitions’ is the common API (Application Programming Interface) for mobile rich media ads that run in mobile apps. MRAID compliant apps all talk the same 'creative language' where things like ad expansion, ad resizing, and getting access to device functionally such as the accelerometer are concerned. This makes it much easier for developers to create rich media ads that will work across multiple apps. For more info about MRAID see here.