It may be called a piece of bread (4)
I believe the answer is:
roll
This clue is a triple definition!
'it may be called' is the first definition.
(I've seen this before)
'a piece' is the second definition.
(thesaurus)
'of' is a link.
'bread' is the third definition.
(I know that roll is a type of bread)
(Other definitions for roll that I've seen before include "Rob while sleeping < to pass" , "Sound of a drum or a list of names" , "Move like a wheel" , "Bread - list - sway" , "Cylinder (of paper etc)" .)