headroom
nounUK /ˈhɛdruːm/
US /ˈhɛdruːm/
Headroom is the empty space above your head when you stand or sit somewhere.
There is plenty of headroom in this tall tent.
OTHER MEANINGS
2. Extra money or time kept in case it is needed.
The budget has some headroom for unexpected costs.
3. The amount by which a company's earnings can grow before hitting a limit.
The firm still has headroom to raise prices.
4. The space above a vehicle or load before it hits something overhead.
The truck barely had enough headroom to pass under the bridge.