A rod raised beneath iron headgear (6)
I believe the answer is:
fedora
'headgear' is the definition.
(fedora is a kind of headgear)
'a rod raised beneath iron' is the wordplay.
'raised' says the letters should be written in reverse (going up in a down clue).
'beneath' is a charade indicator (letters next to each other) (in a down clue, some letters go below others).
'iron' becomes 'Fe' (chemical symbol for iron).
'a'+'rod'='arod'
'arod' written backwards gives 'dora'.
'dora' after 'fe' is 'FEDORA'.
(Other definitions for fedora that I've seen before include "Felt hat with a creased crown" , "Hat for RAF doe" , "Read of (anag) - brimmed felt hat" , "Type of hat" , "Headwear" .)