nod-v; 2 Senses

Sense Number 1: lower and raise (as if) with the head

The wizard's eyes flicked up at the commander, and he nodded his understanding.
'Yeah, that,' Uther nodded at the dead cow, his face serious.
Michelle nodded her head, laughing, 'I'm still going to do that.'
The green moss lay in tufts upon the roof, the grass nodded from the eaves.

VerbNet: wink-40.3.1-1
FrameNet: Gesture,Body_movement
PropBank: nod.01
WordNet 3.0 Sense Numbers: 1, 2, 4

Sense Number 2: lower the head as if falling asleep

Commentary: Includes: NOD OFF

Earnhardt nodded off at the wheel while waiting for the race to start.
The old seer sat nodding at the fireplace.

VerbNet: NM
FrameNet: Body_movement
PropBank: nod.02
WordNet 3.0 Sense Numbers: 3, 5
WordNet Verb Particle Constructions, Multiword Expressions:
nod_off 1