Hanoi bread to ring a bell (4)

I believe the answer is:

dong

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

'ring a bell' is the definition.
'dong' can be an answer for 'ring' (donging is a kind of ringing). I'm not certain of the 'a bell' bit.

I cannot understand how the remainder of the clue works.

Can you help me to learn more?

(Other definitions for dong that I've seen before include "Lear's one had a luminous nose" , "Ding's partner?" , "The --- with a Luminous Nose (Lear)" , "Deep resonant clang - Vietnamese monetary unit" , "Deep ringing sound" .)

I've seen this clue in the Sydney Morning Herald.

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