# actin

> English word · Noun · IPA /ˈæktɪn/ · frequency rank #24,076

## Definitions
1. A globular structural protein that polymerizes in a helical fashion to form an actin filament (or microfilament).
2. One of the six isoforms of actin.

## Etymology
From Ancient Greek ἀκτίς (aktís, “ray”), based on the shape of the filament formed, + -in.

## Easily confused with
- **ain** (https://plainspell.com/en/vs/actin-vs-ain)
- **acts** (https://plainspell.com/en/vs/actin-vs-acts)
- **akin** (https://plainspell.com/en/vs/actin-vs-akin)
- **amin** (https://plainspell.com/en/vs/actin-vs-amin)
- **again** (https://plainspell.com/en/vs/actin-vs-again)
- **actor** (https://plainspell.com/en/vs/actin-vs-actor)
- **admin** (https://plainspell.com/en/vs/actin-vs-admin)
- **Aston** (https://plainspell.com/en/vs/actin-vs-aston)
- **attic** (https://plainspell.com/en/vs/actin-vs-attic)
- **Anton** (https://plainspell.com/en/vs/actin-vs-anton)
- **Alvin** (https://plainspell.com/en/vs/actin-vs-alvin)
- **Alain** (https://plainspell.com/en/vs/actin-vs-alain)
- **Alton** (https://plainspell.com/en/vs/actin-vs-alton)
- **Artie** (https://plainspell.com/en/vs/actin-vs-artie)
- **acton** (https://plainspell.com/en/vs/actin-vs-acton)
- **Armin** (https://plainspell.com/en/vs/actin-vs-armin)
- **Askin** (https://plainspell.com/en/vs/actin-vs-askin)
- **action** (https://plainspell.com/en/vs/actin-vs-action)
- **active** (https://plainspell.com/en/vs/actin-vs-active)
- **acting** (https://plainspell.com/en/vs/actin-vs-acting)

## Common misspellings (7)
`acctin`, `acitn`, `actinn`, `actni`, `acttin`, `atcin`, `catin`

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