Ace from Ace-King
Ace from Ace-King refers to the lead of the ace when holding AKx or longer. Playing standard leads, ambiguity occurs when partner leads a king because he might hold AKx or KQx. Leading the ace from AKx distinguishes these two scenarios. The ace lead creates a new ambiguity - is it from AKx or Axx? - but this is theoretically less common since players often avoid leading an unsupported ace at trick one.