Leader going on demo in Bow (4)
I believe the answer is:
arch
'bow' is the definition.
(I've seen this in another clue)
I can't explain the remainder of the clue.
Can you help me to learn more?
(Other definitions for arch that I've seen before include "Consummate" , "Bridge span" , "Foremost" , "Marble, for example" , "Curved bony structure in the foot" .)