Mercury — perhaps vet may use as part of cure (5,5)
I believe the answer is:
heavy metal
'mercury' is the definition.
Both the answer and definition are singular nouns.
Maybe they are linked in a way I don't understand?
'vet may use as part of cure' is the wordplay.
'use' is an anagram indicator (I've seen 'used' mean this).
'as part of' is an insertion indicator.
'cure' becomes 'heal' (synonyms).
'vet'+'may'='vetmay'
'vetmay' is an anagram of 'avymet'.
'avymet' placed inside 'heal' is 'HEAVY METAL'.
'perhaps' acts as a link.
Can you help me to learn more?
(Other definitions for heavy metal that I've seen before include "Type of rock" , "Lead, say" , "Iron" , "guitar is thrashed in it" , "Typically, lead" .)