Dictionary.com
Thesaurus.com
Synonyms

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

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

"Collins English Dictionary — Complete & Unabridged" 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012
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.

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.

Etymology

Origin of operating system

First recorded in 1960–65

Example Sentences

Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.

"Mac and Windows are the operating systems for the personal computer. OpenClaw is the operating system for personal AI," Nvidia's chief executive Jensen Huang said in a statement.

From Barron's • Mar. 16, 2026

The case claims the shop built into the PlayStation's operating system was designed to make players a "captive class".

From BBC • Mar. 10, 2026

“We’ve rebuilt Salesforce to become the operating system for the Agentic Enterprise, bringing humans and agents together on one trusted platform,” Benioff said.

From Barron's • Feb. 25, 2026

Gen AI, in particular, will move from a co-pilot to an operating system for finance — engaging with stocks, fixed income, derivatives and other assets.

From MarketWatch • Feb. 25, 2026

This is how having a funny brain that runs on a different operating system from other people’s helped me to figure out what had happened.

From "The London Eye Mystery" by Siobhan Dowd

Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023

Idioms from The American Heritage® Idioms Dictionary copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.