Click Define

A Firefox extension that shows the definition of any word, in any language, when you double-click it.

Features

• Double-click any word on any page to see its definition.
• Multilingual definitions via Wiktionary (hundreds of languages).
• Language picker in the popup when a word has entries in multiple languages.
• Pronunciation with IPA and an audio button (English).
• Synonyms & antonyms as clickable chips; click one to look it up; ← to go back.
• Lemma fallback finds "running" → "run", "boxes" → "box", "happily" → "happy".
• Settings page for toggles and preferences.
• Light + dark mode, smart positioning, Esc to dismiss.

Install (development)

1. Open Firefox → about:debugging#/runtime/this-firefox.
2. Click Load Temporary Add-on….
3. Select manifest.json.

Definition sources

Source	Used for	Languages	Key required
Wiktionary REST API	Definitions, parts of speech, examples	Hundreds	No
Free Dictionary API	IPA, audio, contextual syn/ant	English only	No
Datamuse	Thesaurus (syn/ant)	English only	No

Files

• manifest.json - MV3 manifest (Firefox-compatible)
• content.js - double-click handler, fetching, popup rendering
• content.css - popup styles
• options.html, options.css, options.js - settings page
• icon.svg - toolbar icon
• LICENSE - MIT
• PRIVACY.md - privacy disclosure

License

MIT - see LICENSE.