CPU (Central Processing Unit) previously known as microprocessor chip, often abbreviated to processor or CPU.
What CPUs do I have?
$ hwinfo --cpu 01: None 00.0: 10103 CPU [Created at cpu.301] Unique ID: rdCR.j8NaKXDZtZ6 Hardware Class: cpu Arch: X86-64 Vendor: "GenuineIntel" Model: 6.15.11 "Intel(R) Core(TM)2 Quad CPU Q6600 @ 2.40GHz" Features: fpu,vme,de,pse,tsc,msr,pae,mce,cx8,apic,sep,mtrr,pge,mca,cmov,pat,pse36,clflush,dts,acpi,mmx,fxsr,sse,sse2,ss,ht,tm,pbe,syscall,nx,lm,constant_tsc,arch_perfmon,pebs,bts,rep_good,pni,monitor,ds_cpl,vmx,est,tm2,ssse3,cx16,xtpr,lahf_lm Clock: 1600 MHz BogoMips: 4791.54 Cache: 4096 kb Units/Processor: 4 Config Status: cfg=new, avail=yes, need=no, active=unknown
The block in this example is repeated 4 times because there this is a quad-core processor (Units/Processor: 4). The "clock" value is different because this is a 2.40GHz processor, running at 1600 MHz.
To reduce complexity:
$ hwinfo --cpu --short cpu: Intel(R) Core(TM)2 Quad CPU Q6600 @ 2.40GHz, 1600MHz Intel(R) Core(TM)2 Quad CPU Q6600 @ 2.40GHz, 1600MHz Intel(R) Core(TM)2 Quad CPU Q6600 @ 2.40GHz, 1600MHz Intel(R) Core(TM)2 Quad CPU Q6600 @ 2.40GHz, 1600MHz
tells me I have a quad-core processor and 4 processor cores, so one processor with 4 cores, 2.4GHz ones running at 1600MHz.
load average is a measure to tell how busy the CPU is. load average shows the average number of processes waiting for execution. Usually there are three numbers presented where the first show average last minute, second average for last five minutes and the third show average load for the last fifteen minutes.