Aussie river rising in impressive display (5)

I believe the answer is:

array

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

'impressive display' is the definition.
(I've seen this before)

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

Can you help me to learn more?

(Other definitions for array that I've seen before include "Imposing arrangement" , "Impressive exhibition" , "Marshal" , "Impressive display or range of something" , "Impressive arrangement" .)

I've seen this clue in The Independent and The Sun.

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