headroom

Definition

The vertical clearance above someone's head, as in a tunnel, doorway etc; room (space) for one's head.

Etymology

From head + room.

Example Sentences

• "With a rare and beautiful ease one can now ring up a boffin, as I did the other day, and say: "As a price for not opposing our Parliamentary Powers for a new marshalling yard, the Council at X demands that the bridge over X Lane shall have 16 ft. 6 in. headroom. This means steepening our gradient from 1 in 70 to 1 in 65 for half a mile on a 20-chain curve. What difference will this make to the loads of Type "2", "3" and "4" diesels please?". Back comes the answer."
• "The new bridge (6) gives headroom of 13ft at high tide, sufficient for present-day river traffic."
• "[…] the difference between signal-to-noise ratio and overload reserve (headroom) as well as noise (safety) margin (footroom)."