leviathan

/ləˈvaɪəθən/
noun
  1. Something that is extremely large and powerful, especially a government, corporation, or other organization.
    • The country's military is a leviathan that consumes a huge portion of the national budget.
    • The tech leviathan announced plans to build a new headquarters.
    • Small businesses struggle to compete against the leviathan of online retail.
  2. A very large sea creature, especially a whale or a mythical monster of the deep.
    • In the story, the sailors feared the leviathan that lurked beneath the waves.
    • Ancient maps sometimes showed a leviathan swallowing ships.
    • The blue whale is a true leviathan of the ocean.