DirectX 11 is the primary graphics API for Microsoft platforms including Windows, Xbox One, and Windows phone.
DirectX 11 is the latest release of Microsoft's DirectX framework, which is the name of a collection of APIs, containing features to aid in game development. The most commonly used component is Direct3D which can be used to generate both 2d and 3d graphics.
This tag is for any question that involves the use of any of the components in the DirectX 11 framework.