I get way more requests than comments. It's unfair. The word behemoth, as the title implies, has origins in the Bible, where in the book of Job it, alongside the Leviathan, is cited as an example of God's power in creating dangerous creatures. Both monsters later took on a metaphorical usage as "big things", but behemoth specifically is a transliteration of Hebrew b'hemoth. This has several suggested sources, each equally ambiguous and arbitrary. The prevailing notion is that it's a corruption of b'hemah, or "beast", itself probably from a Proto-Semitic root like bhmt that carried connotations of livestock. Another theory is that b'hemah is from Egyptian pehamu, which meant "hippopotamus", a dangerous creature revered by their ancient culture. Even less likely roots have been suggested across the Semitic languages, though all trace back to some kind of bulky animal. All the spellings here are loose phonetic transliterations (remember, no vowels in Egyptian and Hebrew for real) and all go back from Proto-Semitic to Afro-Asiatic.
Adam Aleksic, a freshman studying linguistics at Harvard University, has been described as the internet's sixth most famous etymologist. He has disturbing interests in words, vexillology, geography, board games, limericks, and law, and he loves writing about himself in the third person.
The Etymology Nerd