Lost the right, having sketched sunrise (4)

I believe the answer is:

dawn

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'sunrise' is the definition.
(synonyms)

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

(Other definitions for dawn that I've seen before include "Early morning sing-song?" , "First light" , "Aurora, poetically" , "Aurora was its goddess" , "Begin to appear" .)

I've seen this clue in The Mirror.

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