Great question!
mkdir stands for "make directory".
In the world of computers, a "directory" is just another word for a folder. So, when you use the mkdir command, you are telling Linux to create a new, empty folder for you.
Here is how it works:
mkdir: The action (create a folder).digital_garden: The name you want to give to that folder.
Once you run mkdir digital_garden, you have officially created a new space to store your files, just like right-clicking and selecting "New Folder" on a Windows or Mac desktop!
Would you like to try running it now to see it in action?