DirectX is a collection of APIs that provide access to the display and audio cards of a Microsoft PC.
Using DirectX, a programme can easily determine the hardware capabilities of the machine it is operating on.
These APIs provide access to the advanced features of a PC, such as 3D graphics and high-quality music and audio effects. Software is hence able to run on any Windows-based computer with DirectX compatible hardware and drivers.
The name DirextX was coined as shorthand for the multiple APIs that make up the technology.
Originally the name of these APIs began with Direct and included things such as Direct3D, DirectDraw, DirectPlay, DirectSound and more.