An airfoil for a turbine blade, the airfoil comprising: a first pressure side cavity positioned adjacent a pressure side , the first pressure side cavity configured to receive a coolant ; at least one distinct pressure side cavity positioned adjacent to and fluidly coupled to the first pressure side cavity ; a trailing edge positioned between the pressure side and a suction side ; at least one suction side cavity positioned adjacent the suction side ; and a trailing edge cooling system positioned adjacent the trailing edge and in direct fluid communication with the first pressure side cavity , the trailing edge cooling system comprising a plurality of cooling circuits each including: an outward leg extending axially between the trailing edge and the first pressure side cavity , the outward leg in direct fluid communication with the first pressure side cavity via an opening formed through a side wall ; characterized in having: a return leg extending axially between the trailing edge and the at least one suction side cavity , the return leg in direct fluid communication with the at least one suction side cavity; and a turn positioned adjacent the trailing edge, the turn fluidly coupling the outward leg and the return leg, the cooling system configured to receive a portion of the coolant from the first pressure side cavity . a first pressure side cavity positioned adjacent a pressure side , the first pressure side cavity configured to receive a coolant ; at least one distinct pressure side cavity positioned adjacent to and fluidly coupled to the first pressure side cavity ; a trailing edge positioned between the pressure side and a suction side ; at least one suction side cavity positioned adjacent the suction side ; and a trailing edge cooling system positioned adjacent the trailing edge and in direct fluid communication with the first pressure side cavity , the trailing edge cooling system comprising a plurality of cooling circuits each including: an outward leg extending axially between the trailing edge and the first pressure side cavity , the outward leg in direct fluid communication with the first pressure side cavity via an opening formed through a side wall ; characterized in having: a return leg extending axially between the trailing edge and the at least one suction side cavity , the return leg in direct fluid communication with the at least one suction side cavity; and a turn positioned adjacent the trailing edge, the turn fluidly coupling the outward leg and the return leg, the cooling system configured to receive a portion of the coolant from the first pressure side cavity . an outward leg extending axially between the trailing edge and the first pressure side cavity , the outward leg in direct fluid communication with the first pressure side cavity via an opening formed through a side wall ; characterized in having: a return leg extending axially between the trailing edge and the at least one suction side cavity , the return leg in direct fluid communication with the at least one suction side cavity; and a turn positioned adjacent the trailing edge, the turn fluidly coupling the outward leg and the return leg, the cooling system configured to receive a portion of the coolant from the first pressure side cavity . <EOS>