In association with Afton Chemical Corporation
| Acronym | Definition |
|---|---|
| A/F | air/fuel ratio |
| AAM | Alliance of Automobile Manufacturers |
| AAMA | American Automobile Manufacturers Association |
| AAR | American Association of Railroads |
| ABIL | agriculture-based industrial lubricants |
| ABOT | aluminum beaker oxidation test |
| ACC | American Chemistry Council |
| ACEA | Association des Constructeurs Européens d’Automobiles (European automobile manufacturers association) |
| ACERT | Advanced Combustion Emission Reduction Technology (Caterpillar) |
| ACS | American Chemical Society |