A lot of weapons or just one club (7)

I believe the answer is:

arsenal

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'one club' is the definition.
(I've seen this before)

I cannot understand how the remainder of the clue works.

(Other definitions for arsenal that I've seen before include "Military structure for arms and ammunitions" , "Football club based at Emirates Stadium" , "London football club - magazine" , "Where the guns are and who are The Gunners are" , "Ammunition store or English soccer team" .)

I've seen this clue in The Independent.

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