otter: [OE] The otter is etymologically the ‘wateranimal’. Its name goes back ultimately to an Indo-European *udros, source also of Greek húdrā ‘water-snake’ (the best-known example of which in English is the many-headed Hydra killed by Hercules). This was a derivative of the same base as produced English water. Its Germanic descendant was *otraz, which has become otter in German, Dutch, and English. => water[otter etymology, otter origin, 英语词源]