From Citizendium, the Citizens' Compendium
- Anterior cruciate ligament: One of the four main stabilising ligaments of the knee.
- Allegro Common Lisp: Commercial implementation of the Common Lisp programming language.
- American Classical League: Professional organization which promotes the study of classical civilization at all levels of education in the United States and Canada.
- Arbortext Command Language: Programming language for PTC Arbortext software.
- Asynchronous Connection-Less: Data transmission link in the Bluetooth system.