Daemon
In plain terms
A background process that runs without direct user interaction.
Going deeper
A daemon runs continuously in the background to provide services like web serving or scheduling, often starting at boot. It works behind the scenes.
Under the hood
Conventionally named with a trailing 'd' (sshd, httpd); managed by init systems like systemd.
Examples
sshd, cron, web servers, background services, systemd-managed processes.
Think of it like...
Like building staff who quietly keep services running without guests noticing.