The name Leviathan is a boy's name of Hebrew/Israeli origin meaning "twisted, coiled; in modern Hebrew - whale". Leviathan and is often added to lists like 62 Excellent Names for Pisces Babies and discussed in our forums with posts like "Picky Parents BNG".
From the experts:
Leviathan was a name given to 24 boys in the USA in 2014. It makes a rather unusual Biblical choice, being the name not of a man or angel, but of a sea monster. In literature and popular culture, the term Leviathan has since come to be used as a synonym for any gargantuan, monstrous creature or object (think of the bag in VEEP). Before this meaning turns parents-to-be off, the term leviathan in modern Hebrew simply means whale, making this a great choice for parents looking for an unusual nature name.