The space you have been your head and the car's roof is an example of headroom.
- space or clearance overhead, as in a doorway or tunnel or above the seats of an automobile
- the temporary increase in volume or power that a high-fidelity audio component can accommodate without distortion
- Space above one's head, as in a motor vehicle, above a doorway, or in a tunnel; clearance.
- See dynamic headroom.
headroom - Computer Definition
Attenuation-to-crosstalk ratio (ACR). See ACR.