operating system

American  

[op-uh-rey-ting sis-tuhm] / ˈɒp ə reɪ tɪŋ ˌsɪs təm /

noun

Computers.

1. the collection of software that directs a computer's operations, controlling and scheduling the execution of other programs, and managing storage, input/output, and communication resources. OS

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operating system British  

noun

1. the set of software that controls the overall operation of a computer system, typically by performing such tasks as memory allocation, job scheduling, and input/output control

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operating system Scientific  

/ ŏp′ə-rā′tĭng /

1. Software designed to handle basic elements of computer operation, such as sending instructions to hardware devices like disk drives and computer screens, and allocating system resources such as memory to different software applications being run. Given uniformly designed operating systems that run on many different computers, developers of software do not need to concern themselves with these problems, and are provided with a standard platform for new programs.

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operating system Cultural  

1. The software that allows computer users to run applications with the hardware of a specific system. Microsoft® Windows® or Apple® Computer's OS are examples of operating systems.

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Etymology

Origin of operating system

First recorded in 1960–65

Example Sentences

An Anthropic blog post said weaknesses could be found in “every major operating system and every major web browser when directed by a user to do so.”

From Barron's • Apr. 10, 2026

Then, on its own — without human guidance or help — figured out how to use that flaw to take control of any server running the operating system, using any computer, anywhere in the world.

From Los Angeles Times • Apr. 10, 2026

The company says that Claude Mythos Preview managed to find high-security vulnerabilities in every major web browser and operating system, capabilities too powerful to fall into the hands of bad actors.

From The Wall Street Journal • Apr. 8, 2026

The preview version of Anthropic’s new Mythos model “has already found thousands of high-severity vulnerabilities, including some in every major operating system and web browser,” the company said in a blog post.

From MarketWatch • Apr. 7, 2026

It was so good, in fact, that it became—and remains—the operating system on which literally millions of computers around the world run.

From "Outliers" by Malcolm Gladwell