The Jargon File (version 4.4.7, 29 Dec 2003):

free software
 n.

    As defined by Richard M. Stallman and used by the Free Software movement,
    this means software that gives users enough freedom to be used by the free
    software community. Specifically, users must be free to modify the software
    for their private use, and free to redistribute it either with or without
    modifications, either commercially or noncommercially, either gratis or
    charging a distribution fee. Free software has existed since the dawn of
    computing; Free Software as a movement began in 1984 with the GNU Project.

    RMS observes that the English word ?free? can refer either to liberty
    (where it means the same as the Spanish or French ?libre?) or to price
    (where it means the same as the Spanish ?gratis? or French ?gratuit?). RMS
    and other people associated with the FSF like to explain the word ?free? in
    ?free software? by saying ?Free as in speech, not as in beer.?

    See also open source. Hard-core proponents of the term ?free software?
    sometimes reject this newer term, claiming that the style of argument
    associated with it ignores or downplays the moral imperative at the heart
    of free software.


The Free On-line Dictionary of Computing (30 December 2018):

free software
FOSS
free open-source software

    Software that everyone is free to copy,
   redistribute and modify.  That implies free software must be
   available as source code, hence "free open source software"
   - "FOSS".  It is usually also free of charge, though anyone
   can sell free software so long as they don't impose any new
   restrictions on its redistribution or use.  The widespread
   acceptance of this definition and free software itself owes a
   great deal to Richard Stallman and the Free Software
   Foundation.

   There are many other kinds of "free software" in the sense of
   "free of charge".  See "-ware".

   This dictionary is free in both senses, though since it is
   documentation not software it is distributed under the
   GFDL.

   (2007-02-09)