Or little computing tricks and hacks
I finally found a description of the difference between the physical processor and its cores.
The physical processor in the modern computer comes nowadays with two or four processor cores, respectively called dual or quad-core. These cores are like virtual processors and can handle instructions as if they were standalone.
In the system description of the computer, a single physical processor may appear as two (for dual-core) or four processors (for quad-core), as the system might describe virtual processors and not actual sockets.
To query for the number of processors and cores, in ubuntu use the following command:
grep on “processor” will summarize the number of cores.
(The info on this post was all taken from here.)