at

At War

Acronym for the Appalachian Trail. Used mainly among hikers that have hiked and/or ran the trail, but by other people as well. The Appalachian Trail runs from Georgia to Maine.
"I'm hiking the AT this summer."
"Really? The whole thing???"

AT- stands for anti-tank, as in antitak weapon, rpg (rocket propelled grenade) or panzerfaust
Take that Panther out w/ the AT.

Type of motherboard
I have an AT motherboard in my 8086 baby.

sometimes a nick name for Athena- most of the time is called that by good friends and/or body guard of the moment
hey at! when are you coming to lunch?

acronym for the term "Advanced Technique." Used in various video games including, but not limited to, Smash Bros.
In Super Smash Bros. Melee, WaveDashing is an AT.

the 2 letter acronym that surves no real meaning placed at the front of every single large imperial vehicle in the Star Wars series...
coincidentally; also the first 2 letters of what is possibly the worst phone company, and worst phone company name... ever: AT&T
Clone Trooper: engage the AAT
or
Rebel Soldier: destroy the AT-AT
or
Chad: I fear there is an evil greater than all of the AT-vehicles combined... AT&T

Acronym for automatic transmission; an automobile featuring a gearbox that can automatically change gear ratios based on the car's velocity
My 2005 Nissan Altima 3.5 SE AT OWNS YOU!

the situation sb/sth is in, what sb is doing or what is happening: ◆The country is now at war. ◆ I felt at a disadvantage. ◆ I think Mr Harris is at lunch.
Ellis Boyd 'Red' Redding : I think it is the excitement only a free man can feel, a free man at the start of a long journey whose conclusion is uncertain.