Sea monsters are sea-dwelling mythical or legendary creatures, often believed to be of immense size. Marine monsters can take many forms, including sea dragons, sea serpents, or multi-armed beasts. They can be slimy or scaly and are often pictured threatening ships or spouting jets of water. The definition of a `monster` is subjective, and some .....
• Any large sea animal.
Sea' mon'ster (Zoology) Any large sea animal.