603 (disambiguation)

603 may refer to:

*603 (number), the natural number following 602 and preceding 604
*A year: 603 CE or 603 BCE
*The North American telephone area code 603
*The IBM 603 Electronic Multiplier
*The PowerPC 603 microprocessor
*The socket 603 motherboard socket for the Intel Xeon microprocessor
*Minor planet 603, named Timandra
*The Tatra 603 automobile
*The Bristol 603 automobile
*The Daimler-Benz DB 603 aircraft engine
*The Mercedes-Benz OM603 diesel engine
*The large number 10⁶⁰³, known as ducentillion (USA and modern British) or thousand centillion (traditional British) or centilliard (traditional European)