How Pentium D, Dual core and Core2Duo are different?

[toofan]

I am confused by the the terms Pentium D, Dual Core and Core 2 Duo.
Pentium D is dual core, Dual core is dual core and Core 2 duo is also dual core?
1. Is it true?
2. what is their proper definition ?
3. whats the difference between?

If all have major difference then don't you think that their names should also be different and more clear?

 

[desiibond]

*en.wikipedia.org/wiki/Pentium_D

Pentium D was just two Pentium 4 cores on one Module.
This was succeeded by Core2Duo. Core2Duo is entirely new architecture known as "Core Architecture". *en.wikipedia.org/wiki/Core_architecture

It's this core architecture that shifted the performance advantage to Intel.

Pentium D is one of the worst microprocessors launched (to compete with superiour AMD Athlon X2).

Pentium dual core is based on the same core architecture but are budget oriented. These are low cost dual core processors designed to compete with low end Athlon X2's.

*en.wikipedia.org/wiki/Intel_Pentium_Dual-Core

In the Current Market:

Pentium Dual Core processors are available for as low as Rs. 2.5k
Core2Duo is available from Rs.5.5k (approx).

core2quad is the current performance king (quad core processor) in microprocessor market.
Core2Duo is the current leader in Dual core processor market
Pentium Dual Core is for budget conscious users that competes with Athlon X2 entry level processors.