Cycle round ace country (5)
I believe the answer is:
spain
'country' is the definition.
(Spain is an example)
'cycle round ace' is the wordplay.
'cycle' becomes 'span' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'round' means one lot of letters goes inside another.
'ace' becomes 'i' ('I' can be a synonym of 'ace').
'span' placed around 'i' is 'SPAIN'.
Can you help me to learn more?
(Other definitions for spain that I've seen before include "Take pains to go there" , "Country bordering Andorra" , "part of Europe" , "country of mostly dry mountains, going by air" , "European nation" .)