| Abbreviation | Definition |
|---|---|
| ALTAR | Allows Lives To Acquire Redemption |
| ALTAR | AltaVista Long Term Annual Return |
| ALTAVOZ | Altavoces |
| ALTB | Amicale Laique Tarnos Barthes |
| ALTC | Advanced Low Temperature Combustion |
| ALTC | Aging and Long Term Care |
| ALTC | Annals of Long Term Care |
| ALTC | Atlanta Land Trust Collaborative |
| ALTD | A Light In The Darkness |
| ALTD | Abundant Life Tres Dias |
| ALTD | Advanced Lighting Technology Demonstration |
| ALTD | Apache Longbow Tactical Demonstrator |
| ALTD | Automatic Library Tracking Database |
| ALTE | Apparent Life Threatening Event |
| ALTE | Apparent Life Threatening Events |
| ALTEA | Anomalous Long Term Effects on Astronauts |
| ALTENER | altenerG |
| ALTER | Activities Location Timing Environment Resources |
| ALTER | Alliance for Lobbying Transparency and Ethics Regulation |
| ALTER | altered |