Overview
Behemoth (; , bəhēmōṯ) is a beast from the biblical Book of Job, and is a form of the primeval chaos-monster created by God at the beginning of creation; he is paired with the other chaos-monster, Leviathan, and according to later Jewish tradition both would become food for the righteous at the end-time. Metaphorically, the name has come to be used for any extremely large or powerful entity.
Etymology
The Hebrew word behemoth has the same form as the plural of the Hebrew noun בהמה behemah meaning 'beast', suggesting an augmentative meaning 'great beast'. However, some theorize that the word might originate from an Egyptian word of the form pꜣ jḥ mw 'the water-ox' meaning 'hippopotamus', altered by folk etymology in Hebrew to resemble behemah. However, this phrase with this meaning is unattested at any stage of Egyptian.
Biblical description
The Hebrew word behemoth is only mentioned once in Biblical text, in a speech from the mouth of God in the Book of Job. It is a primeval creature created by God and so powerful that only God can overcome him:
From Wikipedia (CC BY-SA 4.0).