| Aakash | Academic & Science |
| Atto (10¯¹⁸) | Academic & Science |
| angstrom [1 x 10¯¹⁰ meters in length] | Academic & Science |
| Absorptivity | Academic & Science |
| Asymmetrical (or assymetrical) | Academic & Science |
| Assymetrical | Academic & Science |
| Type A (Battery Size) | Academic & Science |
| Helmholtz Energy | Academic & Science |
| symbol for Argon, until 1957 | Academic & Science |
| Aqueous | Academic & Science |
| Advanced | Academic & Science |
| Adjective | Academic & Science |
| Art | Academic & Science |
| Blood Type | Academic & Science |
| Analysis | Academic & Science |
| Atto | Academic & Science |
| The Arts | Academic & Science |
| Anglo American Cataloguing Rule | Academic & Science |
| Accepted | Accounts and Finance |
| Approved | Business |
| Association | Business |
| American Bank Note Company | Business |
| Amortization (Finance) | Business |
| Archives | Business |
| Agilent Technologies | Business |
| Amendment of Application | Business |
| Agilent Technologies Incorporated | Business |
| Aktopia | Business |
| Atom | Chemistry |
| Act | Community |
| Artemis | Community |
| Annihilation | Computing |
| Adventure Mode | Computing |
| Archived | Computing |
| Alpha Token | Cryptocurrency |
| Australian | Earth Science |
| Ampere | Electronics |
| Anode | Electronics |
| Form A (normally Open) Contacts | Electronics |
| Ages | General |
| Aperture | General |
| Accusative | General |
| A-check | General |
| Asexual | General |
| Alex | General |
| Andrei | General |
| Ava | General |
| Accessory | General |
| Aggregate | General |
| Agave | General |
| Annealing | General |
| Apple | General |
| Ape | General |
| Ann | General |
| Awesome | General |
| Apron | General |
| Aqua | General |
| Avance | General |
| Avianca Airlines | General |
| Answer | General |
| Ada | General |
| Appropriate | General |
| Arte | General |
| Accept | Governmental |
| Arbitration | Governmental |
| Accord | Governmental |
| Air Force Training Category | Governmental |
| for Aircraft | Governmental |
| Activism | Governmental |
| Autos | Governmental |
| American | Governmental |
| Alay | International |
| Add | Internet |
| As | Internet |
| Actor | Jobs |
| Against | Maths |
| chemical activity | Medical |
| mass number | Medical |
| Ankle Jerk/Reflex | Medical |
| Accelerations | Medical |
| Anal | Medical |
| Acetum | Medical |
| Actin | Medical |
| Actinomyces | Medical |
| Adenosine | Medical |
| admittance Electricity | Medical |
| Adrenaline | Medical |
| Adriamycin | Medical |
| Adults & Communities | Medical |
| Agar | Medical |
| Akinetic | Medical |
| Alanine | Medical |
| Albino guinea pig | Medical |
| Alcohol | Medical |
| Allele | Medical |
| Allergist | Medical |
| Blood Type A | Medical |
| Vitamin A | Medical |
| Allergy | Medical |
| alveolar gas | Medical |
| Amphetamine | Medical |
| Anaphylaxis | Medical |
| Anion | Medical |
| anoxia/reoxygenation | Medical |
| Anterior | Medical |
| antinuclear antibody (ANA is more commonly used) | Medical |
| apical/radial | Medical |
| Area | Medical |
| Ant | Medical |
| Anteater | Medical |
| radioactivity | Medical |
| Arterial | Medical |
| Arteriolar | Medical |
| Adenine | Medical |
| Animals | Medical |
| Asbestos | Medical |
| Asparagine | Medical |
| Alveolization | Medical |
| Atrial | Medical |
| Atrium | Medical |
| Atropine | Medical |
| augmenting reducing | Medical |
| before (from Latin ante) | Medical |
| Auricular | Medical |
| auris (ear) | Medical |
| ante (before) | Medical |
| Aedes | Medical |
| Artery | Medical |
| Ancyclostoma | Medical |
| Ascaris | Medical |
| Annoying | Messaging |
| Atomic | Physics Related |
| African | Regional |
| Alton Railroad | Regional |
| Agiliance | Softwares |
| Acceleration | Space Science |
| Aft | Space Science |
| Alpha | Space Science |
| Analog Signal | Space Science |
| Angstrom | Space Science |
| Assists | Sports |
| Assist | Sports |
| Ace | Sports |
| All Lines | Telecommunication |
