head·room 
/ˈhɛdˌru:m/ noun
/ˈhɛdˌru:m/ noun [noncount] : the space between the top of your head and a ceiling or roof when you are standing or sitting
▪ There isn't much headroom in the basement. [=the ceiling is low in the basement] ▪ He's looking for a car with a lot of headroom.
▪ There isn't much headroom in the basement. [=the ceiling is low in the basement] ▪ He's looking for a car with a lot of headroom.
