A steel product with prickles (6)
I believe the answer is:
teasel
'with prickles' is the definition.
Although both the answer and definition are singular nouns, I cannot see how they can define each other.
'a steel product' is the wordplay.
'a steel' anagrams to 'TEASEL'.
But, I'm unsure how this is indicated.
Can you help me to learn more?
(Other definitions for teasel that I've seen before include "Spiny flower head" , "Sat Lee down on the spiny herb" , "Sat eel up on the herb" , "Plant with spiny purple flower heads" , "Plant with prickly flower head" .)