So Apple A7 is “System on chip or” or “CPU”? Very confused, in some websites, they have this line:


iPhone 5s

CPU: Apple A7


other websites saying that:


iPhone 5s
System-on-chip: Apple 7
CPU: 1.3 GHz 64bit dual core


other sources saying that


iPhone 5s
System-on-chip: Apple 7
CPU: 1.3 GHz 64bit dual core Apple 7


in Wiki, it said:


  The Apple A7 is a 64-bit system on a chip (SoC) designed by Apple Inc.
  It first appeared in the iPhone 5S, which was introduced on September
  10, 2013. Apple states that it is up to twice as fast and has up to
  twice the graphics power compared to its predecessor, the Apple
  A6. While not the first 64-bit ARM CPU, it is the first to
  ship in a consumer smartphone or tablet computer.


There are 2 sentences:

The Apple A7 is a 64-bit system on a chip (SoC)


&amp; 

  While not the first 64-bit ARM CPU


Wiki also said The A7 features an Apple-designed 64-bit 1.3–1.4 GHz ARMv8-A dual-core CPU, called Cyclone

So System on chip is also CPU? very confused

Then other source compares System on chip and CPU, they said "CPU will not work without other around components" &amp; "System on chip is the combination of CPU &amp; other components into a single chip."
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.