Behemoth

Boyd’s Bible Dictionary:

(water-ox). From the poet’s description a hippopotamus is meant (Job 40:15-24).

Concise Bible Dictionary:

This is a Hebrew word and is now very generally believed to refer to the Hippopotamus (Job 40:15). Jehovah calls the attention of Job to this wonderful animal that he might see the wisdom and power of its Creator.
Hippopotamus

Strong’s Dictionary of Hebrew Words:

Transliteration:
bhemowth
Phonic:
be-hay-mohth’
Meaning:
in form a plural or 929, but really a singular of Egyptian derivation; a water-ox, i.e. the hippopotamus or Nile- horse
KJV Usage:
Behemoth

Jackson’s Dictionary of Scripture Proper Names:

beasts Bel, lord