Real Dictionary

A.T. in American English
abbreviation: Atlantic time

at
preposition: If someone is at school or college, or at a particular school or college, they go there regularly to study.
preposition: You use at to indicate the place or event where something happens or is situated.

At in American English
astatine
abbreviation: achievement test

at in American English 1
on; in; near; by: at is the preposition of general (usually static) location, and is replaced by in, on, etc. when a more precise indication of location is needed
abbreviation: ampere-turn
preposition: in, on, or near

at in American English 2
a monetary unit of Laos, equal to 1⁄100 of a kip
noun: a money of account of Laos, the 100th part of a kip
the chemical symbol for: astatine

at in American English 3
airtight

At in British English
abbreviation for: attainment target
symbol for: ampere-turn
the chemical symbol for: astatine

at in British English 1
preposition: used to indicate location or position

at in British English 2
noun: a Laotian monetary unit worth one hundredth of a kip

at in British English 3
the internet domain name for: Austria

at- in American English
ad-
prefix

at. in American English
abbreviation: atmosphere

at. in British English
abbreviation for: atmosphere (unit of pressure)