A layman says computer and thinks of the whole package- the computer is a singular entity. But when you begin to work with computers you become more aware of the many complex and less-obvious components that make up the whole. A computer is merely the sum of parts- both real and virtual. Each part has a necessary and specific function towards the success of the whole.
The word kernel means the fruit or meat of a nut or seed removed and separate from it's shell and exterior properties. It's a perfect description of what we now call a kernel in computing. The Kernel is the meat of the operating system. It is the vital core of what defines the methodology of operations for a computer. A Kernel directs and facilitates the uses of resources by software and hardware that make up a computer or system of computers as well as facilitating communication between different bits of hardware and software. In many ways, a Kernel is like a conductor in the Orchestra. The conductor cues and directs different parts of the music (software) to be used in conjunction with the necessary instruments (hardware), at the appropriate speed, volume, and place (resource allocation).