Nominal knowledge (3)

I believe the answer is:

ken

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'knowledge' is the definition.
(ken is a kind of knowledge)

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

(Other definitions for ken that I've seen before include "Understanding - boy's name" , "Awareness" , "Know; man's name" , "Notice" , "One's range of knowledge" .)

I've seen this clue in the Evening Standard.

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