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.
the forefinger
a finger used in pulling the trigger of a firearm
difficulty encountered in finger flexion or extension caused by the narrowing of the sheath that surrounds that finger's tendon