King James Bible Dictionary

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 Psalms 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" (Psalms 74:14). As used in Isaiah 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.

Possibly a crocodile
Exodus 18:41; Psalms 104:26

The crooked serpent
Isaiah 27:1

Figurative
Psalms 74:14

(jointed monster) occurs five times in the text of the Authorized Version, and once in the margin of (Job 3:8) where the text has "mourning." In the Hebrew Bible the word livyathan , which is, with the foregoing exception, always left untranslated in the Authorized Version, is found only in the following passages: (Job 3:8; 41:1; Psalms 74:14; 104:26; Isaiah 27:1) In the margin of (Job 3:8) and text of (Job 41:1) the crocodile is most clearly the animal denoted by the Hebrew word. (Psalms 74:14) also clearly points to this same saurian. The context of (Psalms 104:26) seems to show that in this passage the name represents some animal of the whale tribe, which is common in the Mediterranean; but it is somewhat uncertain what animal is denoted in (Isaiah 27:1) As the term leviathan is evidently used in no limited sense, it is not improbable that the "leviathan the piercing serpent," or "leviathan the crooked serpent," may denote some species of the great rock-snakes which are common in south and west Africa.

LEVI'ATHAN, noun [Heb.]

1. An aquatic animal, described in Job 41:1, and mentioned in other passages of Scripture. In Isaiah, it is called the crooked serpent. It is not agreed what animal is intended by the writers, whether the crocodile, the whale, or a species of serpent.

2. The whale, or a great whale.