Meaning "Sea Monster" or "Sea Dragon." It means "twisted" or "having folds." This is often interpreted as referring to a non-mythical, large deep-sea creature like a whale or dinosaur- ancient peoples interpreted it as a mythical whale, or Sea Dragon akin to "Jörmungandr", or some other monster like the "Kraken" and by extension "Cthulu". Job 3:8 - Job is lamenting his own existence because of the suffering he had endured, he asks that those who curse days (enchanters, magi, etc), curse the day he was born, either thus or by rousing the Leviathan. Job 26:13 - This verse does not use the word directly but instead "Fleeing Serpent" or "Crooked Serpent." It speaks of clearing the heaven and wounding this 'serpent'. Job 41:1 - This is the verse in Job that implies he is referring to a real creature, which people know of and fear. Psa 74:14 - These verses are obviously not referring to a literal sea, but a figurative sea, therefore the "Leviathan" & "tannin" are not referring to literal sea-creatures here, but the principalities of the figurative 'sea.' The sea being used to communicate engulfing chaos and inhospitable salinity- no foundation for seeds to take root. Psa 104:26 - These verses seem to be referring to literal sea creatures. Isa 27:1 - Again this verse refers to Leviathan as if it was a figurative term for an adversary. It must be used to refer to the "Great Serpent" or "Dragon" of Revelation, which presides over the figurative "Sea," which he uses to flood the figurative 'Earth' (which offers solid foundation for figurative seeds/ vegetation to grow), much like how the Adversary is labelled "serpent" in the Garden of Eden.