Corresponding mail is distributed on run (7)
I believe the answer is:
similar
'corresponding' is the definition.
('similar' can be similar in meaning to 'corresponding')
'mail is distributed on run' is the wordplay.
'distributed' indicates anagramming the letters.
'on' says to put letters next to each other.
'run' becomes 'r' (cricket abbreviation).
'mail'+'is'='mailis'
'mailis' with letters rearranged gives 'simila'.
'simila'+'r'='SIMILAR'
(Other definitions for similar that I've seen before include "Alike, resembling" , "Having a close resemblance to" , "Appearing the same" , "Akin" , "Of the same kind" .)