Wrong label, tag with error initially, minor detail (9)
I believe the answer is:
bagatelle
'minor detail' is the definition.
Although both the answer and definition are singular nouns, I don't understand how they can define each other.
'wrong label tag with error initially' is the wordplay.
'wrong' is an anagram indicator.
'with' means one lot of letters goes inside another.
'initially' says to take the initial letters.
The initial letter of 'error' is 'e'.
'label'+'tag'='labeltag'
'labeltag' is an anagram of 'bagatlle'.
'bagatlle' enclosing 'e' is 'BAGATELLE'.
Can you help me to learn more?
(Other definitions for bagatelle that I've seen before include "Trinket - game played on a board with balls" , "trifling amount" , "Trivial matter" , "musical composition" , "game at the tables?" .)