Duden online
The authority on German spelling and usage — monolingual definitions, free online.
DictionariesWebsitesToolsFreemiumIntermediateAdvancedB1–C2
What it actually is
Duden is what settles arguments about German spelling and grammar, and the online dictionary gives you definitions in German with declension tables, register labels, synonyms and etymology. Switching to it from a bilingual dictionary is a real milestone around B1. Core lookup is free; the Duden-Mentor writing corrector and some premium content are paid.
What it covers
- Vocabulary
- Writing
- Grammar