Medium Transport; Low Wing; 2 Turbojet Eng
Flight Crew Air Transport Pilot (ATP)
ATC Issue All Types; Deviation / Discrepancy - Procedural Clearance; Deviation / Discrepancy - Procedural Published Material / Policy
Air Traffic Control Issued Advisory / Alert; Flight Crew Rejected Takeoff
Human Factors
We took Runway 27 for takeoff at CVG and then were cleared for takeoff.  As I advanced the thrust levers and the aircraft began to accelerate; before I took my hand off the thrust levers for the FO to set thrust I heard tower announce 'STOP! STOP! STOP!'  I immediately retarded the thrust levers and aborted the takeoff.  While the abort was happening ATC told us we were cleared to takeoff and we informed them we had aborted the takeoff.  ATC then asked why did you abort; was it a 'confusion with call signs?'  We let them know we did not hear a call sign we just heard an announcement on tower to stop.  We cleared the runway; ran the checklists; contacted [operations control] and told them we had done a low speed rejected takeoff; and they told us we were okay to depart.
Air Carrier Captain reported a rejected takeoff after hearing the Tower Controller broadcast STOP STOP STOP without a call sign.