Frame plate as a symbol of good luck (9)
I believe the answer is:
horseshoe
'a symbol of good luck' is the definition.
I can't tell whether this defines the answer.
'frame plate' is the wordplay.
'frame' becomes 'horse' (horse is a kind of frame).
'plate' becomes 'shoe' (shoe is a kind of plate).
'horse'+'shoe'='HORSESHOE'
'as' is the link.
Can you help me to learn more?
(Other definitions for horseshoe that I've seen before include "Steed's footwear" , "Plate nailed to equine hoof" , "Hoof protector" , "which may prove lucky" , "One could be lucky" .)