The forefinger.
One who demonstrates anything, or proves beyond doubt.
An item, particularly a vehicle, used in demonstrations to a customer or user.
An assistant to a lecturer.
One who demonstrates products in a retail environment; a merchandiser.
One who teaches anatomy from the dissected parts.
One who takes part in a demonstration; a protester.
A symbol resembling a hand with the index finger extended, used to draw attention to or indicate something.