As explained by Eva in a separate post (Here), ACC is a new attribute to represent an increase in Hero Accuracy.
This value is calculated into an equation to determine how frequently units succeed with their attacks.
•The accuracy equation is:
•Hero Accuracy scores range from 80 to 360. This gives a range of 100.8% to 103.6% Accuracy.
•Accuracy is a direct counter to Dodge, which can only be found on Phantom King, the Artifact Lightning Rock, or Candy Kane's Skill, Sweet Revenge.
Later, ACC scores will be important for determining the effectiveness of individual heroes, depending on how widely Dodge scores vary and how many new functions (artifacts, talents, skills, etc) might be introduced to increase either ACC or Dodge. This post will be updated in the future to reflect this relationship and possibly give insight into how they will affect game play.