Record is set in Washington (4)
I believe the answer is:
disc
'record' is the definition.
(eg a CD, compact disc)
'is set in washington' is the wordplay.
'set in' is an insertion indicator.
'washington' becomes 'dc' (Washington DC).
'is' placed within 'dc' is 'DISC'.
(Other definitions for disc that I've seen before include "Capital of India" , "Record, CD" , "Compact ---; slipped ---" , "jockey may be after" , "Protein-constituent acid" .)