What is a kernal?

[nightsky]

Is it the core of an os, ie UNIX? Does windows have more than one kernel? I put kernel into find in windows and come up w kernel32.dll and Ikernel.lgc. I am reading about Linux and there it says the kernel is UNIX Core. What I really am wondering is if its the core of an os - what does that mean exactly? Is it a particular style of programing that defines what hardware can be used and how it will be used? Is the code in asci? Is there a particular format and syntax? What does it look like? Please give me a general picture here so i can better understand what I have to focus on when reading about Linux or unix. I have a bk on how to use Caldera Open Linux ver 1.3 and the software so I am going to install that and learn how to use it. Then I have an old compaq I can install Redhat Linux ver 5.2 that I got with a Sams Learn to Program bk. Just curious, Thanks all.