One of several sharp nails left alongside fences (5)
I believe the answer is:
talon
'one of several sharp' is the definition.
Although both the answer and definition are singular nouns, I don't understand how one could define the other.
'nails left alongside fences' is the wordplay.
'fences' says the answer is hidden in the clue (the solution is fenced in by the clue).
'TALON' is hidden within 'nails left alongside'.
Can you help me to learn more?
(Other definitions for talon that I've seen before include "One hooked on bird" , "Raptor's claw" , "Claw; undealt cards" , "ogee moulding" , "Holding part of flier" .)