One of the underpinnings of the stage? (4)
I believe the answer is:
prop
This clue might be a double definition.
'one of the underpinnings' is the first definition.
Although both the answer and definition are singular nouns, I cannot understand how one could define the other.
'the stage?' is the second definition.
The definition and answer can be both man-made objects as well as being singular nouns.
Maybe they are linked in a way I don't understand?
'of' is the link.
Can you help me to learn more?
(Other definitions for prop that I've seen before include "See 5" , "Back up" , "Driving mechanism" , "Support to keep from falling" , "Hold (up), support" .)