Peculiar oblong American sausage (7)
I believe the answer is:
bologna
'sausage' is the definition.
(I know that bologna is a type of sausage)
'peculiar oblong american' is the wordplay.
'peculiar' indicates an anagram (a peculiar or strange ordering of the letters).
'american' becomes 'a' (common abbreviation - e.g. in organisation names).
'oblong' anagrammed gives 'bologn'.
'bologn'+'a'='BOLOGNA'
(Other definitions for bologna that I've seen before include "Italian province" , "North Italian university city" , "Capital of Emilia-Romagna" , "Italian city - smoked sausage" .)