Mechanic held, for a time, specific job (5)

I believe the answer is:

niche

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'job' is the definition.
(thesaurus)

'mechanic held for a time specific' is the wordplay.
'NICHE' is hidden within the letters.
However, I'm not sure how the hidden word is indicated.

Can you help me to learn more?

(Other definitions for niche that I've seen before include "Recess - suitable position" , "Special location" , "Recess in wall for statue" , "Small corner of e.g. market" , "Nook, cranny" .)

I've seen this clue in The Guardian.

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