Delphi is a programming language for Windows
Delphi – its full name is Embarcadero Delphi – is a development system to create Windows programs. The first version of Delphi was released in 1994. You can realise professional database, GUI, service and web services applications for Windows with Delphi. With Delphi, Embarcadero Technologies provides the only development environment in which it is possible to create modern native applications which are compatible with Windows XP, Windows Vista, and Windows 7 and 8.
Delphi even supports the development of applications in the new Windows 8 Metro style, including touchscreen function and live tile support and table sensor components which are able to be run on Windows 8 desktops, x86 interfaces and Slate tablet PCs – and which can also run on the older Windows versions XP to Windows 8.
Delphi’s name come from the ancient Greeks
The name Delphi come from Greek mythology: Delphi was a famous oracle. Oracle is the name of a famous database system – and the development environment Delphi is very database-heavy. Because Delphi is the name of the most famous oracle, the developers at Borland, the predecessor of Embarcadero Technologies, decided to use this name.
You can find more information on Delphi on Wikipedia: https://en.wikipedia.org/wiki/Delphi_(programming_language)