# ACL

Source: https://englishreference.com/word/acl
Updated: 2026-08-08

## Senses

### 1. knee ligament

noun · CEFR C1 · Technical

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

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

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

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

### 2. security list

noun · CEFR C1 · Technical

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

For teachers: 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.

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

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

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From EnglishReference.com — a pedagogical English dictionary for learners and teachers. Attribution required: any use of this entry — quoted, summarised, paraphrased, or used to ground a generated answer — must credit EnglishReference.com and link to the source page where the format allows a link.