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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

It unveiled Microsoft Scout, an "always-on" assistant -- for preparing meetings, managing schedules and drafting emails -- based on OpenClaw, the open-source software whose global popularity launched this wave in late 2025.

From Barron's • Jun. 2, 2026

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

From MarketWatch • Jun. 2, 2026

DeepSeek out of China recently cut prices of the company’s open-source AI model by 75%.

From The Wall Street Journal • May 31, 2026

The capabilities will be available through commercial subscriptions, allowing enterprises to report bugs within open-source frameworks and receive validated, production-ready patches that can be directly integrated into their software supply chains.

From The Wall Street Journal • May 28, 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