https://en.wikipedia.org/wiki/DirectX

Microsoft DirectX is a collection of application programming interfaces (APIs) for handling tasks related to multimedia, especially game programming and video, on Microsoft platforms.

Although DirectX contains a number of sub-components, DirectX is frequently referred to interchangeably with its most popular component, Direct3D, which is used to render 3D graphics. However, in its current form, it does include components for 2D graphics Direct2D, audio XAudio2 and input XInput.