Tibetan’s hiding letter from Greece (4)

I believe the answer is:

beta

'letter from greece' is the definition.
(letter from the Greek alphabet)

'tibetan's hiding' is the wordplay.
'hiding' indicates the answer is hidden within the clue.
'BETA' is hidden within 'tibetans'.

(Other definitions for beta that I've seen before include "Second-class" , "Second-rate" , "2nd letter of Greek alphabet" , "Letter before gamma" , "character in Marathon" .)

I've seen this clue in The Everyman puzzle in The Observer.

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