Webster's Revised Unabridged Dictionary · 1913

Water dog

Water dog

1.
(Zoology) A dog accustomed to the water, or trained to retrieve waterfowl. Retrievers, waters spaniels, and Newfoundland dogs are so trained.
2.
(Zoology) The menobranchus.
3.
A small floating cloud, supposed to indicate rain.
4.
A sailor, esp. an old sailor; an old salt. [Colloquial]