Mobile Pentium Processor?

I’m looking at some laptops from Dell and some of them feature a “Mobile Pentium 4 Processor.” I’m thinking this is what they call a normal processor when they put it in a laptop. If indeed it is “specially made” to be mobile, whatever that entails, I’d like to know. Thanks.

It is my understanding that one of the benefits of the “mobile” processors are that they use less energy so that battery life is extended.Read more here

Mobile processors operate at lower voltage, resulting in lower power usage. They also use a smaller physical package, and feature a technology called “SpeedStep” which varies the processors speed depending on the load. You don’t need a 2Ghz processor when you’re running Word, so why not clock it down to 500Mhz and reduce power usage even further?