Crossword Genius

They're funny forms of greetings (5)

Ross

I believe the answer is:

cards

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'greetings' is the definition.
(card is a kind of greeting)

I don't understand the rest of the clue.

Can you help me to learn more?

(Other definitions for cards that I've seen before include "Christmas post" , "They may be for playing or greeting" , "Odd people" , "52 in a pack" , "With which to play snap or patience, perhaps" .)

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