10ten Japanese Reader (Rikaichamp) oleh Birchill

Look up Japanese words with the hover of a mouse.

After enabling the add-on from the toolbar (or press Alt+R) simply hover over Japanese text and a popup displays corresponding dictionary definitions.

Features:

• Pitch accent information
• Automatically updating dictionaries (updating twice a week)
• Support for non-English dictionaries
• Translation of:
  • Japanese yen amounts (e.g. 30億円) into another currency,
  • Japanese numbers (e.g. 13億5千万 into 1,350,000,000),
  • Japanese-era years (e.g. 昭和５６年、令和元年),
  • 畳/帖 measurements (e.g. 四畳半、12.6 帖),
  • shogi moves (e.g. ☗８三銀引成)
• Recognition of a wide range of grammatical forms (e.g. 兼した, 食べてた, 分からん、じーちゃん、頑張ろー、そーゆー, 買っとく etc.)
• Kanji stroke order animations
• Automatic preview of name entries
• Handling of a wide range of characters (e.g. ㌀, ㋿, 𠏹沢, ８月, Ｂ級グルメ,
  オーサカ)
• Localized into Japanese (so you can study Japanese while you study Japanese!) and Simplified Chinese
• Romaji transliteration
• Copy to clipboard in various formats
• Support for the widest range of Web content (vertical text, SVG images, hidden text etc.)
• Minimal memory usage
• Kanji data for Kanji kentei, Conning references, updated educational levels, heavily reworked kanji components etc.

10ten Japanese Reader aims to be simple, reliable, fast, and always up-to-date.

Twitter/X: @10tenapp