The GNU Project is a free software project, announced in 1983 by Richard Stallman. It initiated the GNU operating system, software development for which began in January 1984. GNU is a recursive acronym that stands for "GNU's Not Unix".
The first milestone was to make a free software operating system. To make this happen, the GNU project began working on an operating system called GNU. This goal of making a free software operating system was achieved in 1992 when the last gap in the GNU system, a kernel, was filled by a third-party Unix-style kernel called "Linux" being released as free software.