Jump To:

• open-source
  open-source

  adjective

  pertaining to or denoting software whose source code is available free of charge to the public to use, copy, modify, sublicense, or distribute.
• open source
  open source

  noun

open-source

American  

[oh-puhn-sawrs, -sohrs] / ˈoʊ pənˈsɔrs, -ˈsoʊrs /

adjective

1. Computers. pertaining to or denoting software whose source code is available free of charge to the public to use, copy, modify, sublicense, or distribute.

2. pertaining to or denoting a product or system whose origins, formula, design, etc., are freely accessible to the public.

---

open source British  

noun

1. 1. intellectual property, esp computer source code, that is made freely available to the general public by its creators

   2. ( as modifier ) Compare closed source

      open source software

---

open-source Scientific  

1. Relating to source code that is available to the public without charge. Open-source code is often enhanced, improved, and adapted for specific purposes by interested programmers, with the revised versions of the code are made available to the public. For example, most of the code in the Linux operating system is open-source.

---

Etymology

Origin of open-source

First recorded in 1960–65

Example Sentences

In February 2024, he sued OpenAI and its boss Sam Altman, saying the firm he helped found had reneged on its non-profit, open source origins by hitching its wagon to Microsoft.

From BBC • Jun. 4, 2026

Proton VPN’s apps are fully open source, allowing independent security verification, with the fourth annual no-logs audit completed by Securitum in August 2025.

From Salon • Jun. 2, 2026

To investigate, the team used an open source simulation tool called AM3 to model realistic blazar populations.

From Science Daily • May 24, 2026

But many of the Chinese products are open source, meaning they publicly share details about the tools and make it easy for users to download and modify them.

From The Wall Street Journal • May 23, 2026

I’d begun writing for a new website, Slashdot.org, an intensely geeky techno/pop-culture site devoted to the open source Linux operating system and to the open source and free software movements.

From "Geeks: How Two Lost Boys Rode the Internet Out of Idaho" by Jon Katz