thac0

Elder Elemental Jester's picture

To Hit Armor Class 0, or a roll needed on a 20 sided die to make a successful attack roll against an armor class of 0.  Number may be modified by the armor class rolling against, as well as by bonuses or negatives to hit said armor class.  For example, if your thac0 was 5, you'd need to roll a 5 or better to hit on a 20 sided die.

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