Row about some rare items (4)
I believe the answer is:
tier
'row' is the definition.
(a tier is a row of things)
'about some rare items' is the wordplay.
'about' says the letters should be written in reverse.
'some' says the answer is hidden in the clue (some parts of the word are used).
'reit' can be found hidden inside 'rare items'.
'reit' in reverse letter order is 'TIER'.
(Other definitions for tier that I've seen before include "'Level, grade (4)'" , "one doing Bond" , "Level within hierarchy" , "Person joining" , "band" .)