# ACA vs an

> English confusable word pair

## The two words

### ACA
*noun · frequency rank #15,316*
Initialism of airspace control authority.

### an
*article · IPA /ˈæn/ · frequency rank #30*
Form of a (all article senses).

## Source
Compiled from Wiktionary via kaikki.org (CC BY-SA). Data vintage: 2026-05-06.
Canonical page: https://plainspell.com/en/vs/aca-vs-an