Long thin loaf (8)
I believe the answer is:
baguette
'long thin loaf' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for baguette that I've seen before include "Long loaf - tube gate (anag)" , "Long French breadstick" , "Narrow French stick loaf" , "A long thin French loaf" , "Bread roll" .)