Bit of seed or stone found in meal (5)
I believe the answer is:
testa
'bit of seed' is the definition.
('testa' is part of 'seed')
'stone found in meal' is the wordplay.
'stone' becomes 'st'.
'found in' is an insertion indicator.
'meal' becomes 'tea' (tea is a kind of meal).
'st' put within 'tea' is 'TESTA'.
'or' is the link.
(Other definitions for testa that I've seen before include "Protective covering" , "Hard shell" , "cover for a seed" , "Seed-coat" , "hard case" .)