Fromwater +‎dog.

waterdog (pluralwaterdogs)

1. Amudpuppy.
2. The maturelarva of anambystomid salamander, particularly that of thetiger salamander (Ambystoma tigrinum).
3. Anaxolotl (Ambystoma mexicanum).
4. A small irregular floatingcloud supposed to indicaterain.

• seadog

• dogwater