Singer seen over in Scotland (4)
I believe the answer is:
alto
'singer' is the definition.
(type of singing voice)
'over in scotland' is the wordplay.
'over' shows that the letters should be reversed in order.
'in' indicates the answer is hidden within the clue.
'otla' is hidden within 'scotland'.
'otla' backwards is 'ALTO'.
'seen' acts as a link.
(Other definitions for alto that I've seen before include "Lowest female singing voice" , "Low female singing voice" , "someone to sing" , "The highest adult male singing-voice" , "Key old > male who scores high" .)