Kernel is a word with at least two different meanings in computer science/software development.
On the one hand, the kernel is a component of the operating system, also called "system kernel". It is the lowest software layer of an operating system, this is where the interaction with the hardware takes place.
On the other hand, the kernel is a term from machine learning. The Kernel is an algorithm (e.g. Support Vector Machine) that allows for example the classification of data sets within a two-dimensional space very precisely by projecting these data into a higher-dimensional space (here: three-dimensional space), so that the classification is very easy.
