1. (often initial capital letter) Bible. a sea monster.
2. any huge marine animal, as the whale.
3. anything of immense size and power, as a huge, oceangoing ship.
4. (initial capital letter, italics) a philosophical work (1651) by Thomas Hobbes dealing with the political organization of society.
1350-1400; Middle English levyathan < Late Latin leviathan ≪ Hebrew liwyāthān
“This 2000-strong bureaucratic leviathan allocates its budgets through the various ministries.”
- Misha Glenny, “Science waxes and wanes in Gorbachov’s age of reform,” New Scientist, 1988