For instance, first row in an examination (7)
I believe the answer is:
ordinal
'for instance first' is the definition.
I can't tell whether this defines the answer.
'row in an examination' is the wordplay.
'row' becomes 'din' (both can mean a loud disturbance).
'in' means one lot of letters goes inside another.
'an examination' becomes 'oral' (oral is a kind of examination).
'din' inserted inside 'oral' is 'ORDINAL'.
Can you help me to learn more?
(Other definitions for ordinal that I've seen before include "Ranking number" , "Numerals such as first and second" , "First, second, third could be such a numeral" , "Roman Catholic service book" , "Type of number" .)