Supply department (3)

I believe the answer is:

arm

I believe this is a double definition.

'supply' is the first definition.
(arming is a kind of supplying)

'department' is the second definition.
(both can mean a division of an organisation)

(Other definitions for arm that I've seen before include "Maybe rifle" , "ready for war" , "What soldiers do" , "Shoulder to fingertip" , "Limb; weapon" .)

I've seen this clue in The Times.

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