sea dog

American Heritage® Dictionary of the English Language, Fourth Edition

1. n. Any of various seals or similar marine mammals.
2. n. Nautical A very experienced sailor.
3. n. See fogbow.

Century Dictionary and Cyclopedia

1. n. The harbor-seal, Phoca vitulina; the sea-calf; also (in California), one of the eared seals, Zalophus californianus. See cuts under Phoca and Zalophus.
2. n. The dog-fish, Squalus acanthias, a kind of shark.
3. n. A sailor who has been long afloat; an old sailor.
4. n. A pirate; a privateer.
5. n. In heraldry, a bearing representing a beast nearly like a talbot or alan, but with the addition of a tail like that of a triton, and sometimes with a sort of serrated fin along the back, continued down the tail. The body is covered with scales.
6. n. In meteorology, the solar halo seen in the mist and fog near the surface of the sea opposite the sun.

Wiktionary

1. n. alternative spelling of seadog.

GNU Webster's 1913

1. (Zoöl.) The dogfish.
2. The common seal.
3. colloq. An old sailor; a salt.

WordNet 3.0

1. n. a man who serves as a sailor