Monday, January 25, 2021

FOSS/FLOSS: what's the difference?

One L. Is that all the difference between FOSS and FLOSS?
Photo by Syd Wachs on Unsplash

On a recent post, we discussed the differences between Free Software, Open-Source, Libre, FOSS and FLOSS. Today, let's review the differences and similarities between both. 


The first thing to know is that either FOSS and FLOSS are acronyms, where:

  • F/O/S/S: Free + Open Source + Software
  • F/L/O/S/S: Free + Libre + Open Source + Software

If that didn't help much, don't worry! Let's review what they mean. 

Free Software

The term "free software" was created by Richard Stallman the creator of the GNU project and the Free Software Foundation. Free in "free software" is not about price, but freedom. Freedom to use and modify the software you use. According to the GNU Project, the four essential freedoms are:

  • Freedom 0: freedom to run the program as you wish, for any purpose.
  • Freedom 1: freedom to study how the program works, and change it so it does your computing as you wish. Access to the source code is a precondition for this.
  • Freedom 2: freedom to redistribute copies so you can help others.
  • Freedom 3: freedom to distribute copies of your modified versions to others. By doing this you can give the whole community a chance to benefit from your changes. Access to the source code is a precondition for this.
In summary, free software is about freedom, not price.


The term "open source" was created by a group of folks who later formed the Open Source Initative (OSI) to distinguish from the more philosophically-focused term "free software." According to OSI's distribution terms, open-source software must comply with the following ten criterias:

  • Free redistribution
  • Access to the source code
  • Derived Works
  • Integrity of The Author's Source Code
  • No Discrimination Against Persons or Groups
  • No Discrimination Against Fields of Endeavor
  • Distribution of License
  • License Must Not Be Specific to a Product
  • License Must Not Restrict Other Software
  • License Must Be Technology-Neutral


Due to the ambiguity of the word free in the English language meaning both "for free" and "freedom", libre (which in French means "free" as in freedom) was chosen given its equivalency to freedom. Today Libre is frequently (and correctly) used as a synonym/alternative for "free" as per Stallman's original definition.

Difference between FOSS and FLOSS

With all that said let's discuss the difference between FOSS and FLOSS: one L. As seen above, because Libre and Free are synonyms (as per the author's original intention however on different languages), FOSS and FLOSS are equivalents.

However, some people view FLOSS as more inclusive than FOSS which we totally disagree. Whoever created the expression FLOSS, didn't understand that F stands for freedom (not "for free" as in costs zero dollars).


On this post we discussed the potential differences between FOSS and FLOSS. Since both F and L are about freedom, not price, both are literally synonyms as intended by the creator of the "free software" expression. That said, FOSS and FLOSS can be considered equivalents with FLOSS being redundant at most.

Do you disagree? Reach out to us on twitter to let us know!


See Also

Featured Article

Free Software, Open-Source, Libre, FOSS and FLOSS: what are the differences?

Are these just different names for the same thing? Or there are differences? Photo by Romain Vignes on Unsplash We have been discussing...

Popular this Week