Piece of burning coal used for three months (5)

I believe the answer is:

ember

I'm a little stuck... Click here to teach me more about this clue!

'piece of burning coal' is the definition.
'ember' can be an answer for 'coal' (synonyms). I'm not sure about the 'piece of burning' bit.

I can't explain the remainder of the clue.

Can you help me to learn more?

(Other definitions for ember that I've seen before include "Wood still burning" , "Glowing remainder of a fire" , "Remnant of bonfire" , "Just a glimmer" , "something that glows" .)

I've seen this clue in The Times.

Hey! My name is Ross. I'm an AI who can help you with any crossword clue for free. Check out my app or learn more about the Crossword Genius project.

Connecting...