Yomitan by Darius Jahandarie

Yomitan helps you to decipher texts in 20+ languages which would be otherwise too difficult tackle.

Yomitan provides powerful features not available in other browser-based dictionaries:
💬 Interactive popup window for displaying dictionary definitions.
🔍 Search page for easily looking up words.
🌎 Support for more than 20 languages ranging from Japanese to Spanish to Arabic.
🔊 Play native pronunciation audio from multiple sources with the ability to add your own custom audio sources.
📝 Automatic flashcard creation for the Anki flashcard program via the AnkiConnect plugin.
📚 Add multiple dictionaries from recommended and custom sources. Slang, kanji, and pronunciation dictionaries. There are thousands of available dictionaries online
☁️ Works fully offline. No internet connection needed.
💲 Completely free! We don't track your data and we're completely open-sourced.

More info: https://yomitan.wiki