Available Definitions:
1) a. - Curved so that the apex hangs down; having the top bent downward.
2) v. i. - To incline the head with a quick motion; to make a slight bow; to make a motion of assent, of salutation, or of drowsiness, with the head; as, to nod at one.
3) v. i. - To be drowsy or dull; to be careless.
4) v. t. - To incline or bend, as the head or top; to make a motion of assent, of salutation, or of drowsiness with; as, to nod the head.
5) v. t. - To signify by a nod; as, to nod approbation.
6) v. t. - To cause to bend.
7) n. - A dropping or bending forward of the upper oart or top of anything.
8) n. - A quick or slight downward or forward motion of the head, in assent, in familiar salutation, in drowsiness, or in giving a signal, or a command.