Abarim Publications' online Biblical Hebrew Dictionary
The root לחה (lhh) does not occur as verb in the Bible, and its existence is assumed because of the curious noun לחי (lehi), meaning jaw or cheek. This noun also exists in Arabic, where it is related to a verb that means to peel off, and in Syriac it means to strip off or erase. Perhaps (and this is a guess) these connections suggest that the jaw of an animal was recognized as the instrument with which an animal grazes or peels bark off a tree or a skin off fruit.
In Hebrew this connection doesn't exist and in stead our noun closely resembles a compound of ל (le), meaning for and חי (hay), meaning life. Whether the Hebrews commonly made that connection isn't clear but the compound לחי (lehay) being ל (le) plus חי (hay) occurs frequently in the Bible. It's for instance the lahai-part of the name Beer-lahai-roi and means "the living". It occurs in Daniel 4:34 with a similar meaning and in 1 Samuel 25:6 it's part of a cheer or blessing, comparable with the familiar לחיים (lahayim!). Most spectacularly is the occurrence of לחי (lehay) in 2 Samuel 23:11, where the Philistines gather either "into a company" or a place called Lehi, which means Jaw.
But whatever the common connection was, the jaw is certainly a remarkable body part. It's essential for chewing food and helping the mouth speak. It cradles the tongue and forms the base of one's face.
This word for jaw appears twenty-one times in the Bible, but mostly in texts that deal with subdual. To catch a creature, one hooks its jaw (Job 41:2, Ezekiel 29:4, 38:4). To steer a creature, one places a bridle in its jaw (Isaiah 30:28). To stop a person from talking, one strikes him on the jaw (1 Kings 22:24, Job 16:10, Micah 5:1).