Bone going spare? (3)
I believe the answer is:
rib
This might be a double definition.
'bone' is the first definition.
(rib is a type of bone)
'going spare?' is the second definition.
The definition and answer can be both man-made objects as well as being singular nouns.
I also know that 'spare' relates to this answer.
Can you help me to learn more?
(Other definitions for rib that I've seen before include "spare one?" , "Poke fun at the bone" , "Hinged rod in umbrella" , "structural member" , "Vein structure in a leaf" .)