Customs applications (4)

I believe the answer is:

uses

I believe this is a double definition.

'customs' is the first definition.
(I know this)

'applications' is the second definition.
(use can mean an application or purpose)

(Other definitions for uses that I've seen before include "Takes (drugs)" , "Functions, applications" , "What an employer does" , "manipulates" , "Operates" .)

I've seen this clue in The Telegraph, The Globe and Mail and The Irish News.

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