First to call round with trendy piece (4)
I believe the answer is:
coin
'piece' is the definition.
(I've seen this before)
'first to call round with trendy' is the wordplay.
'first to' says to take the initial letters.
'round' becomes 'o' (round can mean a round object**).
'with' is a charade indicator (letters next to each other).
'trendy' becomes 'in'.
The first letter of 'call' is 'c'.
'c'+'o'+'in'='COIN'
(Other definitions for coin that I've seen before include "Money; devise (a word)" , "Invent (a new phrase)" , "Penny, say?" , "American quarter, for example" , "Fabricate" .)