Dragon
Easton's Dictionary
(1.) Heb. tannim, plural of tan. The name of some unknown creature inhabiting desert places and ruins (Job 30:29; Ps. 44:19; Isa. 13:22; 34:13; 43:20; Jer. 10:22; Micah 1:8; Mal. 1:3); probably, as translated in the Revised Version, the jackal (q.v.).
(2.) Heb. tannin. Some great sea monster (Jer. 51:34). In Isa. 51:9 it may denote the crocodile. In Gen. 1:21 (Heb. plural tanninim) the Authorized Version renders “whales,” and the Revised Version “sea monsters.” It is rendered “serpent” in Ex. 7:9. It is used figuratively in Ps. 74:13; Ezek. 29:3.
In the New Testament the word “dragon” is found only in Rev. 12:3, 4, 7, 9, 16, 17, etc., and is there used metaphorically of “Satan.” (See WHALE.)
Smith's Dictionary
The translators of the Authorized Version, apparently following the Vulgate, have rendered by the same word “dragon” the two Hebrew words tan and tannin, which appear to be quite distinct in meaning.
The former is used, always in the plural, in (Job 30:29; Psalms 44:19; Isaiah 34:13; 43:20; Jeremiah 9:11) It is always applied to some creatures inhabiting the desert, and we should conclude from this that it refers rather to some wild beast than to a serpent. The syriac renders it by a word which, according to Pococke, means a “jackal.” The word tannin seems to refer to any great monster, whether of the land or the sea, being indeed more usually applied to some kind of serpent or reptile, but not exclusively restricted to that sense. (Exodus 7:9,10,12; 32:33; Psalms 91:13) In the New Testament it is found only in the Apocalypse, (Revelation 12:3,4,7,9,16,17) etc., as applied metaphorically to “the old serpent, called the devil, and Satan.”