A mail-round? (8)

I believe the answer is:

circular

I believe this is a double definition.

'a mail' is the first definition.
(I know that circular is a type of mail)

'round?' is the second definition.
(I know that circular can be written as circular)

(Other definitions for circular that I've seen before include "One sort of saw" , "plug, perhaps" , "Round - pamphlet" , "Ring-shaped" , "Shaped like a ring" .)

I've seen this clue in The Irish Independent.

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