| Acronym | Definition |
|---|
| ALCA | Área de Libre Comercio de las Américas |
| ALCA | Associated Landscape Contractors of America |
| ALCA | Área de Livre Comércio das Américas (Free Trade Area of the Americas) |
| ALCA | Acetyl-L-Carnitine Arginate (pharmaceutical) |
| ALCA | Advanced Light Combat Aircraft |
| ALCA | Alabama Counseling Association |
| ALCA | American Landscape Contractors Association |
| ALCA | Australian Lowline Cattle Association (cattle breeding) |
| ALCA | American Leather Chemists Association |
| ALCA | Association de Lutte Contre l'Ambrosia |
| ALCA | American Lock Collectors Association (Mentor, Ohio) |
| ALCA | Área del Libre Comercio para Las Américas (Spanish: Free Trade Area of the Americas) |
| ALCA | Advanced Load Control Alliance (Paragon Consulting Services, Inc.; Portland, OR) |
| ALCA | Average Linkage Clustering Algorithm |