Tag article in English mine (7)
I believe the answer is:
epithet
'tag' is the definition.
(thesaurus)
'article in english mine' is the wordplay.
'article' becomes 'the' (the 'definite article' part of speech).
'in' indicates putting letters inside.
'english' becomes 'e' (abbreviation).
'mine' becomes 'pit' (down the pit).
'e'+'pit'='epit'
'the' put into 'epit' is 'EPITHET'.
(Other definitions for epithet that I've seen before include "Descriptive adjective" , "Descriptive term used to express a real quality" , "nickname" , "Sobriquet" , "Descriptive word or phrase added to a name" .)