Country dance includes one in ancient festival (7)
I believe the answer is:
holiday
'festival' is the definition.
(thesaurus)
'country dance includes one in ancient' is the wordplay.
'country dance' becomes 'hay' (type of country dance. I am not sure about the 'country' bit.**).
'includes' means one lot of letters goes inside another.
'one' becomes 'i' (Roman numeral).
'in' means one lot of letters goes inside another.
'ancient' becomes 'old' ('old' can be similar in meaning to 'ancient').
'i' placed into 'old' is 'olid'.
'hay' enclosing 'olid' is 'HOLIDAY'.
Can you help me to learn more?
(Other definitions for holiday that I've seen before include "Vacation" , "- leave" , "Day of festivity" , "Time off work" , "Break from work" .)