pawl

Etymology

17th c., perhaps from Low German or Dutch pal (“catch (mechanism)”), or from either French pal (“stake”) or épaule (“shoulder”).

noun

1. A pivoted catch designed to fall into a notch on a ratchet wheel so as to allow movement in only one direction (e.g. on a windlass or in a clock mechanism), or alternatively to move the wheel in one direction.
   A pawl is a sort of catch that fits into a ratchet wheel and pushes it around, or it may be used as a catch to prevent the backward motion of a windlass or the wheel on a derrick. 1910, Victor Appleton, Tom Swift and his Motorcycle
   The nails in the rim of the wheel went ratcheting over the leather pawl and the wheel slowed and came to a stop and the woman turned to the crowd and smiled. 1994, Cormac McCarthy, The Crossing
2. A similar device to prevent motion in other mechanisms besides ratchets.

verb

1. (transitive) To stop with a pawl.