What does double-check mean in four-player chess on chess.com

The rule says: Delivering a double-check is worth +5, and triple-checks are worth +15 Is a double check when I am checking two players at one move checking one player with a normal double check

rules - Escaping a double check - Chess Stack Exchange

4 Player Chess - Chess Terms

How do I challenge a friend to play four player chess? - Chess.com Member Support and FAQs

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4 Player Chess - Chess Forums

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Double Check - Chess Terms

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