Free vs open source: 'free as in freedom', not 'free as in beer'

The single most common misunderstanding in this whole subject is the word free. "Free software" does not mean software that costs nothing. It means software that respects your freedom — to run, study, change, and share it. The English word collides two completely different ideas: free as in price (you paid nothing) and free as in liberty (you have rights). Open source is about the second. You can charge money for free software, and people do. Untangling that one word clears up most of the myths people hold about open source.

"Free" means freedom, not price

The Free Software Foundation puts it as "free as in free speech, not as in free beer." Other languages avoid the trap entirely — French and Spanish distinguish libre (freedom) from gratuit / gratis (no cost) — which is why you'll see the word libre used in English when people want to be unambiguous.

The two ideas are genuinely independent axes:

flowchart TD
    LIBRE["Free as in freedom (libre): the four freedoms are present"]
    GRATIS["Free of charge (gratis): the price is zero"]
    LIBRE --> FS["Free software — FSF's term, ethics first"]
    LIBRE --> OS["Open source — OSI's term, pragmatism first"]
    FS --> SAME["Nearly the same set of approved licenses"]
    OS --> SAME
    GRATIS -. "a separate axis — libre software can be sold" .-> LIBRE

    classDef plain stroke:#7b88a1,stroke-width:2.5px
    classDef key stroke:#a3be8c,stroke-width:2.5px
    class LIBRE key
    class GRATIS,FS,OS,SAME plain

Price and freedom are different axes. "Free software" lives on the freedom axis (highlighted); cost is unrelated. Red Hat built a billion-dollar business selling support for software that is fully libre — gratis and libre are simply not the same question.

Plenty of proprietary software is gratis (zero cost, zero freedom — most "free" apps and games). Plenty of free software is sold for money. Confusing the two is what makes people think open source means "amateur" or "unpaid," when the freedom has nothing to do with the price tag.

Free software vs open source

Within the freedom axis, there are two camps that mean almost the same thing but came from different motives:

Free software is the older term, coined by Richard Stallman and the FSF in the mid-1980s. Its framing is ethical: software freedom is a user's right, and withholding it is wrong.
Open source was coined in 1998 (by figures including Eric Raymond and Bruce Perens) specifically to escape the "free = no cost" confusion and to sound business-friendly. Its framing is pragmatic: open development produces better, more reliable software.

The crucial point: they disagree on philosophy, not on which licenses qualify. The FSF's free-software list and the OSI's approved-license list overlap almost completely. MIT, Apache, and the GPL¹ are all both free software and open source. The split is about why you value openness, not what counts as open.

🔗 Learn more — ¹ Copyleft and the GPL family

FOSS, FLOSS, and the umbrella terms

Because arguing over "free" vs "open source" is tiresome, people invented neutral umbrellas:

FOSS — Free and Open Source Software. Covers both camps without picking a side.
FLOSS — Free/Libre and Open Source Software. The extra L for libre exists precisely to kill the "free as in beer" ambiguity one more time.

Use FOSS or FLOSS when you mean "the whole thing" and don't want to start a philosophy fight. The fork post goes deeper on why the two movements draw the line in the same place.

The myths that follow

Almost every wrong belief about open source traces back to that one word. The common ones, busted:

"Open source means free of charge." No — it means freedom. You can sell it, and companies build whole businesses on paid support, hosting, and services around libre code.
"Open source means non-commercial." No — commercial use is required by the definition (no discrimination against fields of use). A license that bans commercial use is not open source.
"Open source means public domain." No — the code is still under copyright; the author retains it and grants rights via the license. Remove the license and you're back to all-rights-reserved.
"Free software is anti-business." No — it's anti-lock-in. Red Hat, and much of the cloud, are built on it.
"If the source is published, it's open source." No — that's source-available, which can withhold the very freedoms that make it open. Visible source is not the same as granted rights.

Get free = freedom, not price straight and the rest of licensing stops being confusing. The next question is what the freedom actually buys you, which is where the permissive and copyleft families diverge.