kernel
Definitions
The central, most important part of something; the core or essence.
The softer, usually edible part of a nut, seed, or fruit stone contained within the shell.
The core component of an operating system that manages hardware and system resources.
Examples
The kernel of the argument was that the company needed to innovate to survive.
The operating system's kernel manages the communication between hardware and software.
She found a single popcorn kernel stuck in her teeth after the movie.