Run out, curious about stone in platform (7)
I believe the answer is:
rostrum
'platform' is the definition.
(rostrum is a kind of platform)
'run out curious about stone' is the wordplay.
'run out' becomes 'ro' (cricket abbreviation).
'curious' becomes 'rum' ('rum' can be a synonym of 'curious').
'about' means one lot of letters go next to another.
'stone' becomes 'st'.
'rum' put after 'st' is 'strum'.
'ro'+'strum'='ROSTRUM'
'in' acts as a link.
(Other definitions for rostrum that I've seen before include "At which one may conduct" , "Platform for speaker" , "Raised platform" , "beak" , "Platform for public speakers" .)