Wurdahuzdą: Proto-Germanic dictionary

noun masculine a-stem rat The origin of this word (and the related *rattō) is uncertain. It may derive from Proto-Indo-European *Hreh₃d- (‘to scrape, gnaw, scratch’) (whence e.g. Latin rōdō and possibly also, but more indirectly, Latin rādō ), but this is disputed, and Klein says that such a connection does not exist. In view of Welsh rhathu (‘to scrape; to chafe’) (via Proto-Brythonic *rėθid and earlier *ratteti from Proto-Celtic *rasdeti (‘to scrape; to scratch’), cognate with Latin rādō (‘to scrape’)), an ancient Celtic derivative noun like *rattos could conceivably be the source. The word may also go back to an unknown substrate language. Kroonen notes that consonant variation is high in descendant languages, especially in the High German dialects (Middle High German rate, radde, ratte, ratze). Older etymological sources explained the Germanic words as borrowings from Romance, but it is now accepted that this is not the case; Kroonen even asserts that the Romance (and Celtic) words must be borrowed from Germanic. He considers it plausible, however—especially considering dialectal Ratz/Ratze (‘polecat’)—that the Germanic word originally referred to a different animal. The rat itself may have been unknown in Europe at a Proto-Germanic date.