Clearance in a Vehicular Tunnel or Under a Doorway
Puzzle 20 of Reality TV Pack
Question is: Clearance in a Vehicular Tunnel or Under a Doorway
and the answer is: HEADROOM
Word Meaning:
HEADROOM — The vertical clearance above someone's head, as in a tunnel, doorway etc; room (space) for one's head.
Definitions from Wiktionary.