# WHAT

> Highlight words and instantly view clean dictionary definitions.

Canonical page: [https://chrome-stats.com/d/what101](https://chrome-stats.com/d/what101)

## Overview

- **ID:** `what101`
- **Platform:** Firefox
- **Type:** Firefox add-on
- **Status:** Available
- **Publisher:** YAHYA MANSOUB
- **Category:** language-support
- **Daily users:** 1
- **Weekly downloads:** 2
- **Version:** 1.0.0
- **Last updated:** 2026-06-06
- **First published:** 2026-06-03
- **Size:** 226 KB
- **Data as of:** 2026-09-08
- **Store listing:** [Firefox Add-ons Store](https://addons.mozilla.org/firefox/addon/what101/)
- **Privacy policy:** [https://addons.mozilla.org/firefox/addon/what101/privacy/](https://addons.mozilla.org/firefox/addon/what101/privacy/)

## Description

WHAT is a simple dictionary extension that helps you understand words while browsing.

Highlight a word on any webpage and WHAT can show its definition in a clean popup. You can also use manual mode, where highlighted words are saved and shown only when you open the extension.

Features:
- Highlight words to get instant definitions
- Choose between automatic popup mode and manual extension mode
- Select different dictionary languages
- Save words locally for later review
- Manage saved word history
- Clean yellow knowledge-themed interface
- No analytics, ads, or tracking

Saved words and settings are stored locally in your browser. WHAT only sends highlighted words to dictionaryapi.dev when it needs to fetch a definition.

## Rankings

- #110,939 — Overall
- #180 — definition

## Permissions and access

### Permissions

- `storage`
- `activeTab`

### Host permissions

- `https://api.dictionaryapi.dev/*`

### Content script matches

- `<all_urls>`

## Safety

- **Risk impact:** Moderate risk impact
- **Risk likelihood:** High risk likelihood

### Analysis details

- Allows access to all websites, posing a significant security risk as it can monitor and modify data from any visited site.
- This extension has low user count. Unpopular extensions may not be stable or safe.

> Some risk analysis details are omitted from this free response. [Upgrade to view the full analysis](https://chrome-stats.com/pricing).

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Source: [Chrome-Stats](https://chrome-stats.com/d/what101)