(1):

(v. t.) To grind with the teeth; to masticate, as food in eating; to chew, as the cud; to champ, as the bit.

(2):

(v. t.) To ruminate in thought; to consider; to keep the mind working upon; to brood over.

(3):

(v. t.) The jaw.

(4):

(v. t.) As much as is put in the mouth at once; a chew; a quid.