Lever That Keeps a Vehicle Stationary
Puzzle 19 of Celtic Mythology Hard Pack
Question is: Lever That Keeps a Vehicle Stationary
and the answer is: HANDBRAKE
Word Meaning:
HANDBRAKE — (mechanical engineering, automotive, rail transport) A brake in a vehicle, set by hand, and usually locking on until released by hand, enabling its use when parked.
Definitions from Wiktionary.