DirectX is not obvious. DirectX is a collection of libraries, mostly for game programming, they all used to start with "Direct": Direct3D, DirectPlay, DirectSo

DirectX is not obvious. DirectX is a collection of libraries, mostly for game programming, they all used to start with "Direct": Direct3D, DirectPlay, DirectSound, DirectDraw,... Now, DirectX is mostly just Direct3D, for other components, is a bit of a mess, especially since it overlaps with the Xbox branding and components.