Free software (FSF definition) is software that is distributed in a manner that allows its users to run the software for any purpose, to redistribute copies of, and to examine, study, and modify, the source code. The term was coined in 1983, with "free" denoting the broad freedom given to users, rather than software that is free of charge (which is freeware).
The free software movement was launched in 1983 with the primary goal of developing free software replacements for the proprietary software that was at that point heavily relied upon. Projects born from the movement include GNU, Linux-libre, LibreOffice, and, on network servers, Samba, and the Apache web server.
Open-source software is free software distributed under a license approved by the Open Source Initiative. The term was coined in 1998 to address the ambiguity of the term "free". Although historically a source of controversy, the two terms are today treated as largely synonymous.