Answers, in the English Bible, the Hebrew word signifying a sea-monster, huge serpent, etc. Thus in Deuteronomy 32:33 Jeremiah 51:34 Revelation 12:1-17, it evidently implies a huge serpent; in Isaiah 27:1 51:9 Ezekiel 29:3, it may mean the crocodile, or any large sea-monster; while in Job 30:29 Lamentations 4:3 Micah 1:8, it seems to refer to some wild animal of the desert, most probably the jackal. The animal known to modern naturalists under the name of dragon, is a harmless species of lizard, found in Asia and Africa.
These dictionary topics are from American Tract Society Bible Dictionary published in 1859. Public Domain, copy freely.
Rand, W. W. "Entry for 'DRAGON'". "American Tract Society Bible Dictionary".