Ring America after the peak (5)
I believe the answer is:
torus
'ring' is the definition.
(I've seen this before)
'america after the peak' is the wordplay.
'america' becomes 'U.S.' (abbreviation for the United States).
'after' means one lot of letters go next to another.
'the peak' becomes 'tor' (I've seen this before).
'us' put after 'tor' is 'TORUS'.
(Other definitions for torus that I've seen before include "Doughnut-shaped figure" , "Doughnut-shaped solid" , "Architectural moulding" , "Ring shaped like doughnut with hole" , "Ring shape" .)