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• DOS
  DOS

  noun

  any of several single-user, command-driven operating systems for personal computers, especially MS DOS.
• DoS
  DoS

  abbreviation

  denial-of-service.

DOS

¹ American  

[daws, dos] / dɔs, dɒs /

noun

Computers.

1. any of several single-user, command-driven operating systems for personal computers, especially MS DOS.

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DOS ² American  

abbreviation

1. Department of State.

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DoS ³ American  

[daws, dos, dee-oh-es] / dɔs, dɒs, ˈdiˌoʊˈɛs /

abbreviation

1. Computers. denial-of-service.

   DoS protection for web servers.

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DOS British  

/ dɒs /

acronym

1. disk-operating system, often prefixed, as in MS-DOS and PC-DOS; a computer operating system

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Etymology

Origin of DOS

d(isk) o(perating) s(ystem)

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Example Sentences

See Examples For:

DOS DoS

Since IBM chose an Intel CPU for its first PC in 1980, chips based around the x86 architecture have run Microsoft DOS and Windows PCs.

From Barron's ● Jun. 2, 2026

Decart has two main business lines, the fastest-growing of which is known as the Decart Optimization Stack, or DOS.

From The Wall Street Journal ● May 18, 2026

Or 5.25-inch floppies, like some of the DOS versions did.

From The Verge ● Jul. 20, 2022

We’d still be staring at DOS prompts on monochrome screens.

From Seattle Times ● Nov. 20, 2021

E.g., typing dir on a Unix box after a session with DOS.

From The Jargon File, Version 4.2.2, 20 Aug 2000 by Guy L. Steele

Unlike , DoS takes into account the constraints inferred from the current polymorphism, distinguishing negative, neutral and adaptive selection.

From Nature ● Feb. 8, 2012

We also computed the direction of selection, DoS, which is positive with adaptive selection, zero under neutrality and negative when weakly deleterious or new nearly neutral mutations are segregating.

From Nature ● Feb. 8, 2012

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