Place in Idaho, Meridian (4)
I believe the answer is:
home
'place' is the definition.
(synonyms)
'in idaho meridian' is the wordplay.
'in' indicates a hidden word.
'HOME' is hidden in the letters of 'idaho meridian'.
(Other definitions for home that I've seen before include "Place of origin" , "and 23: Host side" , "Place of dwelling" , "chez nous?" , "Residence" .)