Support rigid line, for example (6,3)
I believe the answer is:
wooden leg
'support' is the definition.
The answer and definition can be both man-made objects as well as being singular nouns.
Perhaps there's a link between them I don't understand?
'rigid line for example' is the wordplay.
'rigid' becomes 'wooden' (I can't explain this - if you can you should give a lot more credence to this answer).
'line' becomes 'l' (used when specifying particular lines from a poem).
'for example' becomes 'eg' (short for 'exempli gratia', 'for example' in Latin).
'wooden'+'l'+'eg'='WOODEN LEG'
Can you help me to learn more?
(Other definitions for wooden leg that I've seen before include "Walk-on part" , "Eight lines of verse" .)