We found one dictionary that defines the word to the best of their knowledge:

General (1 matching dictionary)

1. to the best of their knowledge: Merriam-Webster

▸ Words similar to to the best of their knowledge ▸ Usage examples for to the best of their knowledge ▸ Idioms related to to the best of their knowledge ▸ Wikipedia articles (New!) ▸ Words that often appear near to the best of their knowledge ▸ Rhymes of to the best of their knowledge ▸ Invented words related to to the best of their knowledge