| Term | Full Form | Category |
|---|---|---|
| A | Allergist | Others |
| A | Allergy | Others |
| A | Alpha | Others |
| A | Alternative | Others |
| A | Alton Railroad | Others |
| A | alveolar gas | Others |
| A | Alveolization | Others |
| A | Amendment of Application | Others |
| A | American | Others |
| A | American Bank Note Company | Others |
| A | Ampere![]() | Measurement Unit, Electricity |
| A | Anal | Others |
| A | Analog | Others |
| A | Analog signal | Others |
| A | Analysis | Others |
| A | Anaphylaxis | Others |
| A | Ancyclostoma | Others |
| A | Andrei | Others |
| A | Anglo American Cataloguing Rule | Others |
| A | Angstrom | Others |
| A | Animal | Others |
| A | Animals | Others |
| A | Anion | Others |
| A | Ankle Jerk/Reflex | Others |
| A | Ann | Others |
| A | Annealing | Others |
| A | Annihilation | Others |
| A | Annoying | Others |
| A | Anode | Others |
| A | anoxia/reoxygenation | Others |
| A | Ant | Others |
| A | Anteater | Others |
| A | Anterior | Others |
| A | antinuclear antibody (ANA is more commonly used) | Others |
| A | Ape | Others |
| A | Aperture | Others |
| A | apical/radial | Others |
| A | Apple | Others |
| A | Appropriate | Others |
| A | Approved | Others |
| A | Apron | Others |
| A | Aqua | Others |
| A | Aqueous | Others |
| A | Arbitration | Others |
| A | Archived | Others |
| A | Archives | Others |
| A | Area | Others |
| A | Art | Others |
| A | Arte | Others |
| A | Artemis | Others |