Strips used to ventilate WC? (9)
I believe the answer is:
airfields
'strips' is the definition.
The answer and definition can be both man-made objects as well as being plural nouns.
Maybe they are linked in a way I don't understand?
'to ventilate wc?' is the wordplay.
'to ventilate' becomes 'air' (synonyms).
'wc?' becomes 'fields' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'air'+'fields'='AIRFIELDS'
'used' is the link.
Can you help me to learn more?
(Other definitions for airfields that I've seen before include "Where strips are" , "places to land" , "Flying bases" .)