AT

AT or at may refer to:

Geography

Atchison County, Kansas (county code)
The Appalachian Trail (A.T.), a 2,180+ mile long mountainous trail in the Eastern United States

Antigua and Barbuda, World Meteorological Organization country code
Ashmore and Cartier Islands (FIPS 10-4 territory code, and obsolete NATO country code)
At, Bihar, village in Aurangabad district of Bihar, India
Province of Asti, Italy (ISO 3166-2:IT code)
Australia, LOC MARC code

@ (or "at sign"), the punctuation symbol now typically used in e-mail addresses and tweets)
at (command), used to schedule tasks or other commands to be performed or run at a certain time
IBM Personal Computer/AT
- AT (form factor) for motherboards and computer cases
- AT connector, a five-pin DIN connector for a keyboard
AT Protocol, a decentralized social networking protocol by Bluesky
The Hayes command set for computer modems (each command begins with the character string "AT")

Anaerobic threshold, in physiology
Análisis transaccional (Spanish for "transactional analysis"), a psychological method
Antithrombin, a small protein molecule
Ataxia–telangiectasia, an immunodeficiency disorder
Athletic training
Atrial tachycardia

Astatine (symbol At), a chemical element
Ampere-turn (symbol A t), an International System of Units (MKS) unit of magnetomotive force
Attotesla (symbol aT), 10⁻¹⁸ tesla, an SI derived unit of magnetic flux density
Technical atmosphere (symbol at), a physical unit of pressure

Acceptance testing, in engineering
Appropriate technology, an ideological movement to scale technology to be appropriate to its context
Assistive technology, devices for people with disabilities
Anti-tank warfare
Automatic transmission, in vehicles