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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 company had built earlier versions of Composer on the Chinese company Moonshot’s open-source Kimi K2.5 model due to computing constraints.

From MarketWatch • Jun. 19, 2026

Since then, the companies have broadened their collaboration, including initiatives aimed at making Meta's open-source AI models more accessible to Indian businesses and developers.

From BBC • Jun. 19, 2026

Most, if not all, of Baseten’s customers are using a mix of open-source and closed-source models for tasks.

From The Wall Street Journal • Jun. 18, 2026

Factory, a startup founded in 2023 that has created autonomous-coding agents that plug into open-source and closed-source models, reached a valuation of $1.5 billion in April.

From The Wall Street Journal • Jun. 18, 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