Open-source & data licenses

OtterDict is built on open data and open-source software. We're grateful to the projects below and credit them here in line with their licenses. A complete list of software dependencies is available on request.

Dictionary & language data

  • CC-CEDICT, open-source Chinese-English dictionary (~120k entries). Licensed under CC BY-SA 4.0.
  • Unicode Unihan Database, Chinese character metadata (radicals, stroke counts, simplified-traditional variants). Licensed under Unicode License.
  • Tatoeba, a multilingual corpus of example sentences. © Tatoeba contributors, licensed under CC BY 2.0 FR.
  • Make Me a Hanzi, stroke-order data. Dictionary under LGPL v3+, stroke graphics under the Arphic Public License.
  • Oracular, oracle-bone script font (甲骨文) © Peichao Qin, used to display oracle-bone characters on the word detail page. Licensed under SIL Open Font License v1.1.
  • Hán-Việt readings, derived from ph0ngp/hanviet-pinyin-wordlist (© 2024 Phong Phan, MIT License) and Unihan kVietnamese, with in-house editing.

Data we share back

Our dictionary layer is derived from CC-CEDICT, licensed under CC BY-SA 4.0. In line with that license's ShareAlike condition, we offer our adapted version of that data under CC BY-SA 4.0 too.

  • Covered: simplified and traditional headwords, pinyin readings, and the English and Vietnamese definitions with their part-of-speech tags.
  • Not covered: Hán-Việt readings (MIT, ph0ngp), Tatoeba example sentences (CC BY 2.0 FR), per-sense example sentences, AI-generated explanations, HSK material, grammar notes, collocations, and the blog. These are separately licensed or our own work.

Fonts

Software libraries

OtterDict runs on hundreds of open-source libraries under permissive licenses (MIT, Apache-2.0, ISC, BSD). A few we want to credit by name:

  • Lucide, the icon set. Licensed under the ISC License.
  • hanzi-writer, the stroke-order animation library (MIT). Its stroke data derives from Make Me a Hanzi under the Arphic Public License.

Questions about licensing or attribution? Contact us.

Open-source & data licenses, OtterDict