Took horse round in this? (5)
I believe the answer is:
rodeo
'this?' is the definition.
The definition suggests a singular noun which matches the answer.
'took horse round' is the wordplay.
'took horse' becomes 'rode' (rode a horse).
'round' becomes 'o' (round can mean a round object).
'rode'+'o'='RODEO'
'in' is the link.
(Other definitions for rodeo that I've seen before include "stock venue?" , "A bunch of cowboys, showing" , "Wild West show" , "Exhibition of cowboy skills" , "Mounted exhibition" .)