So Apple A7 is “System on chip or” or “CPU”?
A SOC contains more elements than just the CPU (graphics capabilities, sound, IO controllers etc), but the CPU is by far the largest, most complex component within it.  A SOC can be referred to as the CPU, because that's where it is (the rest of the contents  of a SOC are more variable, but there has to be a CPU), but obviously not all CPU can be classified as a SOC.