| Acronym | Definition |
|---|
| ATD | Anthropomorphic Test Dummy |
| ATD | Association for Talent Development (formerly American Society of Training Directors) |
| ATD | Attack the Day |
| ATD | Achieving the Dream |
| ATD | Awakening the Dreamer |
| ATD | Analog to Digital (converter) |
| ATD | Atascadero (Amtrak station code; Atascadero, CA) |
| ATD | Attraction Tickets Direct (various locations) |
| ATD | Advanced Technology Demonstration |
| ATD | Attribute Discovery |
| ATD | Address Transition Detection |
| ATD | Authorized Terminal Distribuitor |
| ATD | Analog to Digital |
| ATD | Active Torque Dynamics |
| ATD | Accredited Tier Designer (Uptime Institute) |
| ATD | Attention to Detail |
| ATD | Atmospheric Technology Division (US National Center for Atmospheric Research) |
| ATD | Assistant Technical Director |
| ATD | Applied Technology Diploma (Florida) |
| ATD | Advanced Technology Development |
| ATD | At the Doctor's |
| ATD | Against the Day (Glasgow band) |
| ATD | Antidepressants |
| ATD | Architectural Technology & Design (various schools) |
| ATD | Anthropomorphic Test Device |
| ATD | Acacia Training and Development (UK) |
| ATD | Actual Time of Departure |
| ATD | Art Teaching Diploma (various schools) |
| ATD | Asynchronous Time Division |
| ATD | Aerosol Transmissible Disease |
| ATD | Automatic Target Detection |
| ATD | Agree to Disagree (internet slang) |
| ATD | Asset Transfer Date |
| ATD | Amused to Death (Roger Waters album) |
| ATD | Applied Technology Division |
| ATD | Aircrew Training Device |
| ATD | Arrival Time Difference |
| ATD | Anti-Thyroid Drug |
| ATD | Auto Trim Design (Fairbanks, AK) |
| ATD | Acquired Toilet Disease (fictitious disease) |
| ATD | All Things Democrat (website) |
| ATD | Associated Tap Dancers (UK) |
| ATD | Attitude Determination |
| ATD | Address Transition Detection (circuit in asynchronous memory) |
| ATD | Apprenticeship and Training Division |
| ATD | Anti Terrorist Department (gaming) |
| ATD | Adjustable Time Delay |
| ATD | Aid to the Totally Disabled |
| ATD | Automated Test Designer (software; @YourSide Consulting) |
| ATD | Along Track Distance (aviation) |
| ATD | Automated Thermal Desorber (gas chromatography analysis column type) |
| ATD | Aerospace Technology Division (Library of Congress; formerly Aerospace Information Division) |
| ATD | 6-Etioallochol-1,4-Diene-3,17-Dione (aromatase inhibitor) |
| ATD | Associação Terras Dentro |
| ATD | Alzheimer's Type Dementia (clinical disorder) |
| ATD | Applied Thermodynamics (physics) |
| ATD | Aided Target Detection |
| ATD | Atherothrombotic Disease |
| ATD | Association des Techniciens de Dialyse (French: Association of Dialysis Technicians) |
| ATD | Abrams Travel Data Services |
| ATD | Aquitaine Transmission Distribution (French automotive parts company) |
| ATD | Available to Deploy |
| ATD | Authorized Terminal Distributor |
| ATD | Anti-Tank Ditch |
| ATD | Alliance Tchadienne pour la Démocratie et le Développement (Chadian Alliance for Democracy and Development, Chad) |
| ATD | Authorization Termination Date |
| ATD | Automated Tactical Data Link |
| ATD | Air and Toxics Division |
| ATD | Accelerated Titration Design |
| ATD | Assistant Train Dispatcher (NYC Transit Authority) |
| ATD | Active Threat Defense (Cisco) |
| ATD | Acceptance and Takeover Date |
| ATD | Antitheft Device |
| ATD | Automatic Tube Dispenser |
| ATD | Astronaut Translation Device |
| ATD | Automated Training Device |
| ATD | Adaptive Threshold Detector |
| ATD | Aero Tech Designs (Coraopolis, PA) |
| ATD | Audio Tone Detector |
| ATD | Automatic Tone Detector (Sprint) |
| ATD | Association of Telecommunications Dealers |
| ATD | ATM Test Development |
| ATD | Actuals To Date |
| ATD | AUTOVON Tandem Digital |
| ATD | Automatic Target Designation |
| ATD | Assignment and Transmittal Document (SAIC stock) |
| ATD | Average to Date |
| ATD | Aviation Test Directorate |
| ATD | Air Technician Detachment |
| ATD | Advanced Technologies Demonstration (ARPA/Bell Atlantic) |
| ATD | Amphibische Technische Dienst (Dutch) |
| ATD | Anti Theft Discount (insurance) |
| ATD | Assistance Technique Directe (French: Direct Technical Assistance) |
| ATD | All Terrain Drilling Pty Ltd (Australia) |