Weight running amok, girl having seconds (9)

I believe the answer is:

kilograms

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'weight running amok girl having seconds' is the definition.
I can't tell whether this defines the answer.

'running amok girl having seconds' is the wordplay.
'running' is an anagram indicator.
'having' says to put letters next to each other.
'seconds' becomes 's'.
'amok'+'girl'='amokgirl'
'amokgirl' anagrammed gives 'kilogram'.
'kilogram'+'s'='KILOGRAMS'

Can you help me to learn more?

(Other definitions for kilograms that I've seen before include "Metric weights" , "Metric units of weight" , "Stones substitute" .)

I've seen this clue in The Telegraph.

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