Kotoba uses JMdict, copyright Jim Breen and the Electronic Dictionary Research and Development Group (EDRDG), under Creative Commons Attribution-ShareAlike 4.0. EDRDG does not endorse this application.
English edition dated 2026-09-12, with 218765 entries. English definitions are identified in the interface. Kotoba’s independently authored book translations are displayed separately.
The English XML edition has been converted to compact JSON. Spelling, reading and sense restrictions, usage notes and source tags are retained. Search and a noun filter are applied in the browser. The converted dictionary data are distributed under the same CC BY-SA 4.0 license. This attribution does not claim EDRDG material as Kotoba’s own work.
The project includes an update procedure in scripts/update-dictionary.py. Refresh the official data at least monthly before distributing a new package. Updating the dictionary does not modify saved study progress or the word snapshots in saved games.