Atm and Asynchronous transfer mode

Atm noun - A unit of pressure: the pressure that will support a column of mercury 760 mm high at sea level and 0 degrees centigrade.

Asynchronous transfer mode is a synonym for atm. In some cases you can use "Asynchronous transfer mode" instead a noun "Atm".

Asynchronous transfer mode noun - A means of digital communications that is capable of very high speeds; suitable for transmission of images or voice or video as well as data.

Atm is a synonym for asynchronous transfer mode. You can use "Atm" instead a noun phrase "Asynchronous transfer mode".