Change on-off device (6)

I believe the answer is:

switch

I believe this is a double definition.

'change' is the first definition.
(switch is a kind of change)

'on-off device' is the second definition.

(Other definitions for switch that I've seen before include "Swap" , "Change or exchange" , "Change; flexible shoot" , "Contact maker or breaker" , "Change or cane" .)

I've seen this clue in The Telegraph.

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