dragon, sea-monster, serpent, whale

“Dragon” From Boyd’s Bible Dictionary:

(serpent). An animal of the lizard species. Evidently a wild beast, as a jackal (Job 30:29; Isa. 34:13; Psa. 44:19; Jer. 9:11; Mic. 1:8); sea-serpent (Gen. 1:21); land-serpent (Ex. 7:9-12; Deut. 32:33); devil (Rev. 12:3-17).

“Whale” From Boyd’s Bible Dictionary:

The Hebrew original translated “great whales”
(Gen. 1:21) is used of “serpents” (Ex. 7:9; Deut. 32:33), and of the “crocodile” (Ezek. 29:3; 32:2). The name belongs to sea monsters (Job 7:12; Isa. 27:1). It is thought that the shark of the Mediterranean is meant (Jonah 1:17; Matt. 12:40).

“Dragon (Tannin, δράκων)” From Concise Bible Dictionary:

It may signify any great serpent or sea monster, symbolical of a huge destructive creature. Nations doomed to destruction and desolation, including Jerusalem, are said to become habitations of dragons (Isa. 34:13; Isa. 35:7; Jer. 9:11; Jer. 10:22; Jer. 51:37). Pharaoh, king of Egypt, is called the great dragon (Ezek. 29:3). As one of God’s creatures the dragon is called upon to praise Jehovah (Psa. 148:7). In the New Testament the dragon is a type of Satan and those energized by him. In Revelation 12:3 the “great red dragon, having seven heads and ten horns,” is symbolical of Satan’s power in the form of the Roman empire: it endeavored, in the person of Herod, to destroy Christ when born. In Revelation 13:2, 4 it is Satan who gives the resuscitated Roman empire in a future day its throne and great authority. In Revelation 13:11 The Antichrist, who has two horns like a lamb, speaks as a dragon. In Revelation 16:13 it is Satan, and in Revelation 20:2 he is described as “that old serpent, which is the Devil and Satan.”

“Monster, Sea” From Concise Bible Dictionary:

The Hebrew word is tannin, and is used for any huge creature whether of sea or land (Lam. 4:3). The word is also translated “whales,” “dragons” and “serpents.”
Humpback Whale

“Sea Monster” From Concise Bible Dictionary:

See MONSTER.

“Whale” From Concise Bible Dictionary:

The word tannin (Gen. 1:21; Job 7:12; Ezek. 32:2); and κῆτος (Matt. 12:40); refer to any sea monsters, without defining any particular one. In the case of Jonah the Hebrew word is dag, or dagah, a fish; it may not have been a whale: sharks have been known to swallow men entire, and whatever fish it was that swallowed him, it was a miracle that preserved him alive, and caused him to be safely landed on shore again. It is only by denying the miracle that any difficulty arises. The Hebrew word tannin, is also translated in the AV “dragon,” “sea monster,” and “serpent.”
Humpback Whale

Strong’s Dictionary of Hebrew Words:

Transliteration:
tanniyn
Phonic:
tan-neen’
Meaning:
or tanniym (Ezek. 29:3) {tan-neem'}; intensive from the same as 8565; a marine or land monster, i.e. sea-serpent or jackal
KJV Usage:
dragon, sea-monster, serpent, whale