headroom

n [U] overhead space, esp above a vehicle; clearance 头上空间（尤指机动车的上方）; 净空高度: There is not enough headroom for buses to go under this bridge. 这座桥梁下面的净空高度不够, 公共汽车不能通行.

head-shrinker, head-waters, headache, headband, headboard, header, headgear, heading, headlamp, headland, headless, headlight, headline, headlong, headman, headmaster, headmaster, headmistress, headphones, headquarter, headquarters, headscarf, headship, headstone, headstrong, headway, headword, heady, heal, healer, healing, health, health centre, health farm, health food, health inspector, health service, health visitor, health-care, healthcare, healthful,