Crossword Genius

What might secure bottom, but not one side (7)

Ross

I believe the answer is:

arsenal

'one side' is the definition.
(English football club or side)

I don't understand the remainder of the clue.

(Other definitions for arsenal that I've seen before include "Eleven" , "favoured by some football supporters" , "Collection of weapons" , "array of weapons" , "Where the guns are and who are The Gunners are" .)

I've seen this clue in The Guardian.
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