Many a song is earthy (4)
I believe the answer is:
clay
'is earthy' is the definition.
I can't tell whether this definition defines the answer.
'many a song' is the wordplay.
'many' becomes 'c' (C is the Roman numeral for l00).
'a song' becomes 'lay' (lay is a kind of song).
'c'+'lay'='CLAY'
Can you help me to learn more?
(Other definitions for clay that I've seen before include "Raw material for pottery" , "Earth for pottery" , "Court surface" , "Soft wet earth that can be fired" , "Brick/pottery material" .)