Cable is wires and/or fibers contained in jacket, either rubber or plastic. Cable is used in theater to connect lights, microphones, monitors, speakers, power sources, dimmers, and well, everything. Cable comes in a variety of thicknesses, and should always be coiled loosely, not around one's arm or twisted. Cable is designated first by gauge (square area of conductor) and then by number of conductors. Thus the most common power cable in the theatre is 12/3 [12 gauge, 3 conductor (hot, neutral, and ground)]. Microphone cable (e.g. Belden 8412) with XLR connectors is usually 20g/2c+shield. "Wire" is by definition, a single conductor. A cable contains multiple wires. Technically the term "4/0 Feeder Cable" is incorrect--it should be "feeder wires." See http://www.powerstream.com/Wire_Size.htm for more information about wire sizing.