Dead on the money

Does anyone know what the phrase "dead on the money" mean? I've searched everywhere and all that comes up is the game, or law & order...?

One meaning of "dead," and the one that's relevant here, is exact or precise, as in dead center, or dead solid perfect, or dead ringer. "On the money" means also implies precision with regard to relevance. An observation can be said to be "on the money" when it seems true and insightful. "Dead on the money" is a statement of absolute relevance.