Definition of "AT"

(software) Initialism of assistive technology.  examples

(US, Navy) Initialism of auxiliary tugboat.  examples

(US, sports) Initialism of anaerobic threshold.  examples

(fan fiction) Initialism of alternate timeline.  examples

(aviation, navigation) Initialism of aerotriangulation.  examples

Initialism of appropriate technology.  examples

(firefighting, aviation) Abbreviation of air tanker.  examples

Initialism of activity theory.  examples

(military) Initialism of anti-tank.