seamount       
noun [ C ]  geology specialized uk/ˈsiː.maʊnt/ us/ˈsiː.maʊnt/
 海(底)山
a mountain under the sea
  As many as 100,000 seamounts are submerged under the ocean. 海洋之下淹没着多达10万座海山。 
 He has dived to seamounts with summits more than 3,000 feet down. 他曾下潜到海山,山顶向下有3000多英尺深。 
 Compare: tablemountguyot
 - More examples
 - The group was studying seamounts in the ocean south of New Caledonia.
 - Waves break when they hit an underwater obstruction like a reef or seamount.
 - These fish live in the open ocean and return to the seamounts to breed.