A city, not on for harbouring source of medicinal nut (6)

I believe the answer is:

almond

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'nut' is the definition.
(almond is a type of nut)

I don't understand how the remainder of the clue works.

(Other definitions for almond that I've seen before include "Fruit for marzipan" , "one of the nuts" , "Nut used in marzipan" , "Oval-shaped nut" , "Yellowish brown" .)

I've seen this clue in The Times.

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