What the horse that came second was called? (5,4)

I believe the answer is:

place name

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'horse that came second was called?' is the definition.
Although both the answer and definition are singular nouns, I cannot understand how one could define the other.

I don't understand the remainder of the clue.

Can you help me to learn more?

(Another definition for place name that I've seen is " Map identifier".)

I've seen this clue in the Evening Standard.

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