Definitions for "Pinned"
Entrapment of the boat/paddler on an immoveable object by the force of the water. Bow of the boat held vertically in a steep rapid or waterfall with the nose of the boat trapped.
To be held in place by the current, usually against a rock or other obstruction. It's a dangerous situation for boaters. See Broach and Entrapment.
Held immobile (but not helpless) in a grapple. Opponents other than the character maintaining the pin gain a +4 bonus to attack rolls against a pinned creature.
the dislocations in a crystal get tangled or attached to atoms of an alloying agent.
fastened with a pin or staple; "the stapled papers"
To ride with the throttle wide open.