A socket is the physical socket where the physical CPU capsules are placed. A normal PC only have one socket.
Cores are the number of CPU-cores per CPU capsule. A modern standard CPU for a standard PC usually have two or four cores.
And some CPUs can run more than one parallel thread per CPU-core. Intel (the most common CPU manufacturer for standard PCs) have either one or two threads per core depending on CPU model.
If you multiply the number of socket, cores and threads, i.e. 2*6*2, then you get the number of "CPUs": 24. These aren't real CPUs, but the number of possible parallel threads of execution your system can do.
Just the fact that you have 6 cores is a sign you have a high-end workstation or server computer. The fact that you have two sockets makes it a very high-end computer. Usually not even high-end workstations have that these days, only servers.
