Xdn

xdn , abbrev., D&Dism an abbreviation denoting the number and kind of dice to be rolled, where "x" is the number of dice, and "n" is the number of sides the dice have. [GJ1]
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Addendum: As an example, "3d6" means three six-sided dice. Along these lines, six-sided dice can be referred to as "d6," plural "d-sixes"; ten-sided dice as "d10" or "d-tens"; and percentile dice as "2d10s" or "d100." Although this notation originated with D&D, it is in common use across the gaming spectrum. [GJ1]