Fireplace bit (5)
I believe the answer is:
ember
'fireplace bit' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for ember that I've seen before include "Remnant of bonfire" , "Glower" , "Glowing remainder of a fire" , "Fire remnant" , "Glowing coal; type of goose" .)