LOD.lu is the official app for the Lëtzebuerger Online Dictionnaire, designed to document the Luxembourgish language. Originating from the Règlement grand-ducal in 1999, this app serves as an orthographic reference and translation tool in German, French, English, and Portuguese. Users can explore translations, example sentences, proverbs, synonyms, pronunciation guides with audio files, IPA transcriptions, and sign language videos. The app also features info boxes containing additional linguistic and historical insights beyond standard dictionary entries.

With a user-friendly interface, LOD.lu offers an error-tolerant search function across the five supported languages. Advanced search capabilities allow users to refine results based on criteria like part of speech, phonetics, or language register. Expressions are categorized into various topics such as job descriptions, animals, insults, vehicles, and more. The Zenter fir d’Lëtzebuerger Sprooch oversees the maintenance and development of LOD.lu, mandated by the law promoting the Luxembourgish language.