A length boxers go to, to avoid KO (8)

I believe the answer is:

distance

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'a length' is the definition.
(I know that length can be written as distance)

I don't understand the rest of the clue.

(Other definitions for distance that I've seen before include "to make big winning margin" , "See 3" , "A far-off point" , "Full extent of fighting" , "standoffishness" .)

I've seen this clue in The Globe and Mail.

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