nod
UK[nɒd]US[nɑːd]
v
To move your head down and then up again quickly to show agreement, greeting, or as a sign.
v
To let your head fall forward when you are sleeping in a chair.
n
An act of nodding your head.
Etymology
The word 'nod' is a classic example of onomatopoeic or expressive formation in English, originating in the late Middle English period. It is thought to imitate the quick, dipping motion of the head itself, a process where the sound of the word evokes its meaning. This places it in a category with other expressive verbs for simple body movements, such as 'shrug' or 'jerk'. Over centuries, its meaning expanded from the simple physical motion to encompass the conventional social signals conveyed by that motion, such as agreement or acknowledgment.
Analysis
This is a simplex word of Middle English origin, likely imitative or expressive in nature. It is not productively formed from smaller, identifiable morphemes in modern English.
Examples
She asked if he understood, and he gave a slow nod.
He began to nod off during the long lecture.
A nod from the manager was all the approval she needed.