The term FOSS originated in the early 1980s from the Free Software Foundation (FSF) and the GNU Project led by Richard Stallman (Creator of GPL) to promote software freedom and address the ambiguity associated with the term “free software”.

The term “Libre Software” was actually introduced after FOSS in the early 2000s, sometime around 2002, alongside terms like “software libre” and FLOSS (Free/Libre Open Source Software).

The term “free software” in the context of FOSS was introduced only a few years before FOSS by Richard Stallman with the Free Software Movement and was criticized for being confusing and ambiguous with the historical use of the term that dates all the way back to the 1960s that defines it as any software free of cost.

Not only is the term “FOSS” not modern, it predates all other terms except “free software” which it follows closely after.