headroom; vertical clearance; maximum height
Technical term used in civil engineering, architecture, and transportation to describe the vertical space available under a bridge, beam, or overhead structure. Often measured from the road or water surface to the lowest point of the structure above.
The vertical clearance of this bridge is 4.5 meters.
The headroom was designed high so that large trucks can pass.
Standard kanji spelling for this technical term.
Mixed kanji-kana spelling; less common but still used.
Compound of 桁 (けた, 'beam' or 'girder') and 下 (した, 'under' or 'below'), literally meaning 'under the beam'.