The jaw has many different functions. It can be used to bite or to chew food. It also has an important role in speech.
Therefore, a jaw in a dream can represent power, aggression, nourishment or self-expression.
If you dream of a jaw that is biting someone, you could be repressing feelings of anger or you could desire dominance over someone.
A jaw that is held closed tightly can also represent anger. A tightly closed jaw can also represent stubbornness or an inability to express yourself.
A chewing jaw in a dream symbolizes a need to find a way to provide yourself with emotional nourishment.
A jaw in a dream may symbolize the entrance to the Underworld, and therefore, death.