also eighteen-zero-zero, D&D-ism
1. in Advanced Dungeons & Dragons, 2nd. Ed., the highest possible Strength stat for a mortal player character.
2. describing the best possible. Ex: She’s not too bright, but she’s 18-00 in the looks department.
Addendum: In the original Dungeons & Dragons, 18 was the highest possible score for any stat, unless the character was a demigod. To placate players who wanted their Arnold Schwarzenegger-wannabe characters to have higher-than-18 Strength stats, 2nd. ed. added a 1-100 bonus system, to describe gradations of super-strength between 18 (human maximum) and 19 (demigod). So, for instance, a character might have 18-35 Strength, which wasn’t as good as 18-50 Strength. The new maximum was 18-00.