- D — a programming language.
- Designed by Walter Bright as an improved C, avoiding many of the design problems of C (e.g., extensive pointer manipulation, unenforced array boundaries, etc.).
- daemon — a process in an operating system that runs in the background.
- It is falsely considered an acronym for Disk And Execution Monitor. According to the original team that introduced the concept, "the use of the word daemon was inspired by the Maxwell's demon of physics and thermodynamics (an imaginary agent which helped sort molecules with differing velocities and worked tirelessly in the background)" The term was embraced, and possibly popularized, by the Unix operating systems which supported multiple background processes: various local (and later Internet) services were provided by daemons. This is exemplified by the BSD mascot, John Lasseter's drawing of a friendly imp.
- Debian — a Linux distribution.
- A portmanteau of the names Ian Murdock, the Debian Project creator, and Debra Lynn, Ian's then girlfriend and future wife.
Read more about this topic: List Of Computer Term Etymologies