Crossword Genius

Greetings letter from abroad with ring for papa (5)

Ross

I believe the answer is:

aloha

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'greetings letter' is the definition.
The answer and definition can be both related to communication as well as being singular nouns.
Maybe you can see an association between them that I can't see?

I don't understand the remainder of the clue.

Can you help me to learn more?

(Other definitions for aloha that I've seen before include "Hello from Honolulu?" , "16 across in Hawaii" , "Hawaiian farewell" , "A Hawaiian welcome" , "Hawaiian hello or goodbye" .)

I've seen this clue in The Times.
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