Definition of "headroom" []

• Space above one's head, as in a motor vehicle, above a doorway, or in a tunnel; clearance. (noun)
• Electronics Dynamic headroom. (noun)

American Heritage(R) Dictionary of the English Language, Fifth Edition. Copyright (c) 2011 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

• "PERFORMANCE: In a luxury car, power is less about maximum speed and acceleration than the equivalent to what audiophiles call "headroom" - the capacity to deal instantly and effortlessly with any demand on the system."
• "-- Wide supply voltage range of +2.5 V to +18 V and rail-to-rail output swing allow for increased headroom, which is critical for audio analog-to-digital converter (ADC) front ends and digital-to-analog converter (DAC) post filters, including TI's PCM42xx and PCM17xx devices."
• "Everyone, including people in the third row, get at least 40 inches of headroom, which is unusual."