Noah Webster's New International Dictionary of the English Language
1. (v. t.) To bite and grind with the teeth; to masticate.
2. (v. t.) To ruminate mentally; to meditate on.
3. (v. i.) To perform the action of biting and grinding with the teeth; to ruminate; to meditate.
4. (n.) That which is chewed; that which is held in the mouth at once; a cud.