Is back treated by Yankee here?

I believe the answer is:

sickbay

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'here?' is the definition.
Although both the answer and definition are singular nouns, I don't understand how one could define the other.

'is back treated by yankee' is the wordplay.
'treated' is an anagram indicator.
'by' says to put letters next to each other.
'yankee' becomes 'Y' (phonetic alphabet: alpha, bravo, charlie etc.).
'is'+'back'='isback'
'isback' with letters rearranged gives 'sickba'.
'sickba'+'y'='SICKBAY'

Can you help me to learn more?

(Other definitions for sickbay that I've seen before include "room for improvement" , "Room for ill people" .)

I've seen this clue in The Daily Mail.

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