Definition - What does Linux Kernel mean?
The Linux kernel is an operating system (OS) kernel defined as Unix-like in nature. It used in different operating systems, mostly in the form of different Linux distributions.
The Linux kernel was the first truly complete and prominent example of free and open-source software that prompted its wide adoption and received contributions from thousands of developers.
Techopedia explains Linux Kernel
The Linux kernel was created in 1991 by Linus Torvalds, a student at Finland’s University of Helsinki. It quickly gained ground as programmers adapted source code from other free software projects in order to extend the kernel's functionality.
Torvalds started with a task switcher written in the 80386 assembly language, as well as a terminal driver, and then posted it to the comp.os.minix Usenet group. It was rapidly adapted by the MINIX community, which contributed insights and code to the project.
The Linux kernel grew in popularity because GNU’s own kernel, GNU Hurd, was unavailable and incomplete, and the Berkeley Software Distribution (BSD) OS was still encumbered by legal issues. With help from the developer community, Linux 0.01 was released on September 17, 1991.