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

4 Player Chess - Chess Terms

Double Check - Chess Terms

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Double Check - Chess Terms

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Four-player chess - Wikipedia

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Chess Tactics: Fork, Pin and Discovered Check - Remote Chess Academy

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