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• 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.

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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

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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.

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Etymology

Origin of open-source

First recorded in 1960–65

Example Sentences

The AI models Meta released before Wang’s arrival were all open-source, meaning developers could freely download and use them.

From The Wall Street Journal • Jun. 4, 2026

The company offers free, open-source quantum software, but it doesn’t have its own commercial machines yet.

From Barron's • Jun. 3, 2026

E-commerce company Alibaba Group has also been investing heavily in AI, with its Qwen models widely regarded as top-tier open-source models within the developer community.

From The Wall Street Journal • Jun. 3, 2026

“Widespread take-up of the considerably cheaper, and more flexible, open-source models globally would also be concerning.”

From MarketWatch • Jun. 2, 2026

At the moment, he had NT 5, NT 4, Work Station, Windows 98, and he and Eric had begun fooling around with Linux, the complex, open-source software system rapidly spreading across the world.

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