- Warm-blooded
- body temperature is controlled internally and is maintained at a constant level; endothermic
- Water column
- vertical depth of water; area between the surface of the ocean and the ocean floor
- Water vascular system
- system of fluid-filled canals and structures that aid in locomotion and food gathering
- Wetlands
- biologically productive areas b ordering estuaries, salt marshes and swamps that are occasionally flooded by tidal or river
- Whorl
- single turn of a spiral shell of a mollusk. A body whorl is the msot recently formed turn of a spiral shell terminating in an aperture.
- Wrack
- any marine vegetation cast up on the shore by wave action, example, kelp
