seamount

noun

1. a submarine mountain rising several hundred fathoms above the floor of the sea but having its summit well below the surface of the water.

noun

1. a submarine mountain rising more than 1000 metres above the surrounding ocean floorCompare guyot

n.by 1908, from sea + mount (n.).

1. A large underwater mountain, usually conical in shape and at least 1,000 m (3,280 ft) above the ocean floor. Seamounts are usually isolated and are volcanic in origin.