This sort of room calls for ample space (5)
I believe the answer is:
elbow
This might be a double definition.
'this sort of room' is the first definition.
Although both the answer and definition are singular nouns, I cannot understand how one could define the other.
'ample space' is the second definition.
The answer and definition can be both body parts as well as being singular nouns.
Perhaps there's a link between them I don't understand?
'calls for' is the link.
Can you help me to learn more?
(Other definitions for elbow that I've seen before include "Sharp bend in a road or river" , "Nudging joint?" , "sharp turn" , "Barge" , "Limb hinge" .)