Asian dog covering miles (5)
I believe the answer is:
tamil
'asian' is the definition.
(Tamil is an example)
'dog covering miles' is the wordplay.
'dog' becomes 'tail' ('tail' can be a synonym of 'dog'**).
'covering' means one lot of letters goes inside another.
'miles' becomes 'm' (common abbreviation).
'tail' placed around 'm' is 'TAMIL'.
(Other definitions for tamil that I've seen before include "One in race" , "Dravidian people of India and Sri Lanka" , "Language of southern India and Sri Lanka" , "Asian language" , "An official language of Sri Lanka" .)