Debian was founded by Ian Murdock in 1993, and the name combines his first name with that of his then-girlfriend, Debra. It is run entirely by volunteers under a written constitution, a Social Contract and the Debian Free Software Guidelines. Those guidelines later became the basis of the Open Source Definition.
Debian does not release on a fixed date: a new stable version ships “when it is ready”, which in practice is about every two years. Each release is named after a Toy Story character. Stable releases get around three years of security support from the security team, then two more years from the Debian LTS team, and paid Extended LTS beyond that. Its APT package manager and huge package archive are used by hundreds of derivatives, most notably Ubuntu.