le·vi·a·than /lɪˈvaɪəθən/
  海中怪獸,巨物
  Le·vi·a·than n.
  1. An aquatic animal, described in the book of Job, ch. xli., and mentioned in other passages of Scripture.
  Note: ☞ It is not certainly known what animal is intended, whether the crocodile, the whale, or some sort of serpent.
  2. The whale, or a great whale.
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  leviathan
       n 1: the largest or most massive thing of its kind; "it was a
            leviathan among redwoods"; "they were assigned the
            leviathan of textbooks"
       2: monstrous sea creature symbolizing evil in the Old Testament
  Leviathan
     a transliterated Hebrew word (livyathan), meaning "twisted,"
     "coiled." In Job 3:8, Revised Version, and marg. of Authorized
     Version, it denotes the dragon which, according to Eastern
     tradition, is an enemy of light; in 41:1 the crocodile is meant;
     in Ps. 104:26 it "denotes any large animal that moves by
     writhing or wriggling the body, the whale, the monsters of the
     deep." This word is also used figuratively for a cruel enemy, as
     some think "the Egyptian host, crushed by the divine power, and
     cast on the shores of the Red Sea" (Ps. 74:14). As used in Isa.
     27:1, "leviathan the piercing [R.V. 'swift'] serpent, even
     leviathan that crooked [R.V. marg. 'winding'] serpent," the word
     may probably denote the two empires, the Assyrian and the
     Babylonian.