Mature article about key Mediterranean region (6)

I believe the answer is:

aegean

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'mediterranean region' is the definition.
(as in the Aegean Sea)

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

Can you help me to learn more?

(Other definitions for aegean that I've seen before include "Greek sea" , "Sea between Greece and Turkey" , "Branch of Mediterranean" , "area of sea" , "Sea bordering 20 ac" .)

I've seen this clue in The Times.

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