nod

(noun) a sign of assent or salutation or command.

(noun) the act of nodding the head.

(verb) express or signify by nodding. Example: "He nodded his approval."

(verb) lower and raise the head, as to indicate assent or agreement or confirmation. Example: "The teacher nodded when the student gave the right answer."

(verb) let the head fall forward through drowsiness. Example: "The old man was nodding in his chair."

(verb) sway gently back and forth, as in a nodding motion. Example: "The flowers were nodding in the breeze."

(verb) be almost asleep. Example: "The old man sat nodding by the fireplace."