A positive sign (4)

I believe the answer is:

plus

I believe this clue is a double definition.

'a positive' is the first definition.
(I know that positive can be written as plus)

'sign' is the second definition.
(plus sign is a kind of sign)

(Other definitions for plus that I've seen before include "Something more" , "mark for arithmetic" , "An advantage; positive" , "Advantage; also" , "Benefit" .)

I've seen this clue in the Evening Standard and The Globe and Mail.

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