English Reference
noun

ACL

n.
acl

  1. 01 C1 Advanced Technical Medicine

    Stands for Anterior Cruciate Ligament. This is a very important part of your knee that helps it stay stable.

    Abbreviation for Anterior Cruciate Ligament. This refers to one of the key ligaments that helps stabilise the human knee joint.

    Simple

    The football player had to miss the whole season after he tore his ACL during a game.

    In context

    The surgeon explained that a complete ACL tear would require reconstructive surgery followed by several months of intensive physical therapy.

    Usage

    Usually used with 'the' or a possessive pronoun like 'his' or 'her'.

    Teacher's tip

    Commonly heard in sports news; learners should know it refers specifically to a knee injury.

  2. 02 C1 Advanced Technical Computing

    Stands for Access Control List. It is a list of rules that says who can see or use certain files on a computer.

    Abbreviation for Access Control List. A table or list that tells a computer operating system which access rights each user has to a particular system object.

    Simple

    The IT manager updated the ACL to make sure only the finance team could see the payroll files.

    In context

    By implementing a strict ACL on the server, the administrator successfully restricted sensitive data access to authorised personnel only.

    Usage

    Often used as a countable noun in technical documentation.

    Teacher's tip

    This is a highly specialised term used by network administrators and developers.

Signed from Feyenoord for around £21m last year, he suffered a season-ending ACL injury on international duty in October.

The Guardian· 6 Aug 2026
This entry
Level C1 · Advanced
Frequency Frequent
Updated