Free Software is software which respects the users' four freedoms:
- Freedom 0: To run the program how one wishes.
- Freedom 1: To study the software and modify the source code
- Freedom 2: To redistribute the software
- Freedom 3: To redistribute one's modified copies
The opposite of free software is proprietary software because the software is controlled by its proprietor and not its users.
In other languages, the term is found as libre software.
The software mentioned on this wiki is generally of the free/libre variety - although it may be discussed in the context of proprietary systems such as Android.
The term "open-source"
Many people assume "free software" to mean software free of charge. The term for that is actually freeware. This has posed a challenge in communicating the message of freedom which is the purpose of free software. In the late 90's an alternative term "open-source" was created represented by the open-source movement.
The term "open-source" seems to put emphasis on only freedom 1 (the freedom to study the software). The criticism is that this term, though marketable and comprehensible, does not really reflect what it is supposed to stand for. And that as a result will lead astray from the other three freedoms. This has somewhat already happened as in the case of openwashing, so-called "ethical" software (open-source proprietary software).
This is mostly semantical, that is one can take open-source to refer to free software and visa-versa.
Some alternative terms have been proposed such as FOSS, FLOSS, libre software and even liberty software.