Headroom is a term used to describe the amount of space between the top of an object and the ceiling. It is commonly used in architecture, engineering, and aviation. ROOM is a four-letter word meaning an area enclosed by walls and a roof. CLEARANCE is a nine-letter word meaning the distance between two objects or the amount of space available. MAX is a three-letter word meaning the greatest or highest amount. Together, these words can be used to describe headroom as the maximum amount of space between the top of an object and the ceiling.