Ventilation route found in staircase (6)
I believe the answer is:
airway
'in staircase' is the definition.
The answer and definition can be both man-made objects as well as being singular nouns.
Perhaps they are linked in a way I don't understand?
'ventilation route' is the wordplay.
'ventilation' becomes 'air'.
'route' becomes 'way' (way is a kind of route).
'air'+'way'='AIRWAY'
'found' is the link.
Can you help me to learn more?
(Other definitions for airway that I've seen before include "Respiratory tract" , "Ventilation passage" , "radio channel" , "Breathing passage" , "passage for inspiration" .)