i am bit confused in following CPU keywords
3) n-core processor
5) "number of processors" means ? It's physcial or logical ?
And on what basis (from above listed) parallelism (MAXDOP) is decided ?
A socket is a place on the motherboard where a CPU/processor (a physical piece of silicon with electrical contacts on the bottom) can be placed.
A core/processor is, equivalent to a single core CPU, that can do only one thing at once. I.e. if you have one core, then one query can be actively executing at once, OR the operating system can be doing something, etc. If you have two cores (either a single dual-core package, or two mono-core packages), then you can run two queries, one query that's executed in two parallel streams, one query + an OS task, etc.
Note that some modern AMD chips have 2 integer cores per floating point core, making core counts even trickier.
Dual/Tri/Quad/Hex/Octo/Mangy/etc.-core relates to how many integer cores are on each physical piece of silicon.
A hyperthread/(logical) processor is a "logical" core that is much more limited, generally provided in pairs per core. Many modern CPU's support Hyperthreading, so a 1-socket, quad-core, hyperthreading enabled machine would show 8 "logical processors", and actually be able to do 4 things at once, though with certain workloads on certain generations, additional processes gain a performance advantage. A 1-socket, quad-core, non-hyperthreaded machine would show 4 "logical processors".
"Number of processors" is a statement you must always seek clarification on. Sometimes it means sockets, sometimes integer or floating point cores, sometimes hyperthreads.
MAXDOP is related primarily to hyperthreads.