Half of it used during a meal may be silver (5)
I believe the answer is:
metal
'be silver' is the definition.
(I've seen this in another clue)
'half of it used during a meal' is the wordplay.
'half of' suggests halving the letters.
'used during' is an insertion indicator.
'it' halved is 't'.
't' going inside 'meal' is 'METAL'.
'may' is the link.
(Other definitions for metal that I've seen before include "Copper, perhaps" , "Broken stones" , "employed in making roads" , "Musically it can be heavy" , "Eg, titanium" .)