AWD vs 4WD

Hi,

Can somebody please explain me the difference between a 4 wheel drive and All wheel drive. 

Then we have some cars specifications which mention 2WD, i.e. 2 wheel drive.

For somebody who has not grown up with cars around, these terms do create a confusion in mind. So, can somebody throw a light on this?

Harsh

There is so much to write on this, its almost like an essay.  I will write in detail later - am at work now.  But for now here's some reading material for you:

http://www.4x4abc.com/4WD101/ 

http://auto.howstuffworks.com/four-wheel-drive.htm 

http://4wheeldrive.about.com/cs/offroadingtips/a/aa021203a_2.htm 

Hey Steeroid. Amazing information. I knew about 4WD and how it works...but this has further enhanced my knowledge. Infact there were so many queries that I had in mind and are very beautifully answered here.

Thanks for that.

In short, 4WD puts power to all 4 wheels throughout (whenever enabled). Good when you need to ensure traction and power at all times whereas an AWD (all-wheel drive) distributes power to just the rear wheels, and then puts power to the front ones as needed as in when slipping is sensed in the front two!