ATM

ATM is an initialism with the following meanings:

Automated teller machine or automatic teller machine, a cash dispenser or cash machine
Association of Teachers of Mathematics in the UK.
Adobe Type Manager, font management software from Adobe Systems
Advanced Traffic Management and Arterial Traffic Management, terms used in the intelligent transportation system industry
Air Traffic Management, or Air Traffic Control
Amateur telescope making
Anti-tank Missile
Ass to mouth, a sexual act mostly observed in pornography
Asynchronous Transfer Mode, a telecommunications protocol
At-the-money, a term used in option pricing
Ataxia telangiectasia mutated (molecuar and cell biology, biochemistry), is a protein kinase that plays a critical role in response to certain types of DNA damage
ATM is a Russian clone of the ZX Spectrum
ATM is the IATA code for Altamira Airport in Altamira, Pará, Brazil.
At the moment, an abbreviation often used as a shorthand during a typed internet chat session referring to something you are currently doing. (E.g. I'm drinking tea ATM.)
atm is an abbreviation for atmosphere, a unit of atmospheric pressure.