DOS
Abbreviation with 4 meanings
| Stands for | United States Department of State |
|---|---|
| Meanings | 4 |
| Categories | Government & Politics, Technology & Computing, Medical |
| Also written | DoS |
DOS has four meanings. The most common are United States Department of State (US federal agency) and Denial of service (cybersecurity); it can also stand for Disk operating system and Day of surgery.
Meanings of DOS at a glance
| # | DOS stands for | Context |
|---|---|---|
| 1 | United States Department of State | Government & Politics › US Federal Agency |
| 2 | Denial of service | Technology & Computing › Cybersecurity |
| 3 | Disk operating system | Technology & Computing › Computer |
| 4 | Day of surgery | Medical › Surgical |
1. United States Department of State
Government & Politics · US Federal Agency Abbreviations
Conducts US foreign policy, runs more than 270 embassies, consulates and other posts, and issues passports and visas through its Bureau of Consular Affairs. The department is led by the Secretary of State, who is fourth in the presidential line of succession.
Example: The DOS travel advisory raised the country to Level 4, telling Americans not to travel there.
Created in July 1789 as the Department of Foreign Affairs and renamed weeks later, it was the first executive department organized under the Constitution. News outlets usually say "the State Department"; DOS appears mainly in government documents and job postings. The same letters mean disk operating system in computing and denial of service (DoS) in cybersecurity.
2. Denial of service (DoS)
Technology & Computing · Cybersecurity Abbreviations
An attack that makes a system unavailable to its intended users, either by flooding it with traffic or by exploiting a flaw that crashes it or exhausts its resources. Unlike DDoS, a basic DoS attack comes from a single source.
Example: A malformed request could trigger a DoS by sending the parser into an infinite loop.
Single-source floods are easy to block, so most large attacks today are distributed. Application-level bugs, such as regular expressions that backtrack catastrophically or "zip bombs", can take down services with tiny inputs, and vulnerability databases classify many crash bugs as DoS issues. Capitalized as DoS to distinguish it from DOS, the disk operating system.
3. Disk operating system
Technology & Computing · Computer Abbreviations
Family of early PC operating systems loaded from disk and controlled by typed commands, most famously MS-DOS. The term also covers other disk-based systems of the era, such as Apple DOS and DR-DOS.
Example: We launched the game from DOS by typing its name at the C:\ prompt.
DOS dominated IBM-compatible PCs from 1981 until Windows 95 absorbed it; Windows 95, 98 and Me still started from a DOS layer. The free FreeDOS project keeps a compatible system alive, and emulators such as DOSBox run old games. Do not confuse it with DoS, written with a lowercase o, which is a denial-of-service cyberattack.
4. Day of surgery
Medical · Surgical Abbreviations
Scheduling and nursing shorthand for the date of an operation and the activities on that day: arrival, check-in, final assessment, site marking and transfer to the operating room. Patients admitted the morning of their operation are called "DOS admits".
Example: Patient is a DOS admit; arrive 6:00 a.m. at the surgical admissions desk.
Instructions often specify which medications to take on the DOS with a sip of water and which to hold. Clinics label tasks "DOS" versus "pre-op" to separate work done on the day from earlier preparation. In computing DOS means disk operating system.
Related abbreviations
More US federal agency abbreviations
- DOGE – Department of Government Efficiency
- DOI – United States Department of the Interior
- DOJ – United States Department of Justice
- DOL – United States Department of Labor
- DOT – United States Department of Transportation
- DoW – Department of War
- EAC – U.S. Election Assistance Commission
- EBSA – Employee Benefits Security Administration
See all 152 US federal agency abbreviations →
More cybersecurity abbreviations
- DH – Diffie-Hellman (key exchange)
- DKIM – DomainKeys Identified Mail
- DLP – Data loss prevention
- DMARC – Domain-based Message Authentication, Reporting and Conformance
- DPI – Deep packet inspection
- DSA – Digital Signature Algorithm
- E2EE – End-to-end encryption
- EAP – Extensible Authentication Protocol
See all 119 cybersecurity abbreviations →
This entry is for general education and is not medical advice. Abbreviation use varies between institutions; always confirm in context.