Tribal rag turns out to be rock (9)
I believe the answer is:
gibraltar
'be rock' is the definition.
(I've seen this before)
'tribal rag turns out' is the wordplay.
'turns out' indicates an anagram.
'tribal'+'rag'='tribalrag'
'tribalrag' is an anagram of 'GIBRALTAR'.
'to' acts as a link.
(Other definitions for gibraltar that I've seen before include "British overseas territory" , "UK territory" , "Fortified rock-headland at southern tip of Spain" , "British dependency" , "Colony on rock" .)