Number row featured in exam (7)
I believe the answer is:
ordinal
'number' is the definition.
(ordinal number is a kind of number)
'row featured in exam' is the wordplay.
'row' becomes 'din' (both can mean a loud disturbance).
'featured in' is an insertion indicator.
'exam' becomes 'oral' (oral exam is a kind of exam).
'din' inserted inside 'oral' is 'ORDINAL'.
(Other definitions for ordinal that I've seen before include "Relating to series order" , "First and second, say" , "First, for One" , "Old Iran (anag)" , "Kind of number defining position in series" .)