Dictionary definition of "turntable":
- a circular horizontal platform that rotates a phonograph record while it is being played
- a rotating stand used in sculpture, metalwork, and ceramics
- a circular horizontal rotating platform equipped with a railway track, used for turning locomotives, as in a roundhouse
- a rotating platform or disk, such as a lazy Susan

Dictionary definition of "phonograph":
- any sound-reproducing machine using records in the form of cylinders or discs.
[Origin: 1825–35 in sense “phonogram”; 1877 for the “talking phonograph” invented by T. A. Edison; phono- + -graph]

If just say DJ turntable, you could be talking about a CD turntable, or phonograph turntable.

Technics SL-1210M5G Pro Turntable (plays records)
http://www.guitarcenter.com/shop/product/buy_technics_sl1210m5g_pro_turntable?full_sku=102063013

Technics SL-DZ1200 Digital Turntable (plays CDs)
http://www.guitarcenter.com/shop/product/buy_technics_sldz1200_digital_turntable?full_sku=102582459

A phonograph stereo being called a phonograph & a phonograph turntable being called a turntable is pretty commonly accepted.

Also if you’re talking about antique wind up phonograph cylinder players & wind up 78 rpm phonograph record players, you would say phonograph.

So I guess the best answer would be a phonograph is the whole system that produces sound from a record & a turntable is specifically the component that plays the record in a system that produces sound from a record.