Domain Name
Also known as: Web Address, Web Name
A domain name is the name of your place on the internet, and you rent it the way you rent a library book.
Every place needs a name so people can tell somebody else about it.
On the internet the name is something like mialemonade.com, and here is the surprising part: nobody gets to keep a name forever for free. You rent it. Every year you pay a small amount, and while you are paying, the name is yours and nobody else can use it.
If you stop paying, somebody else can take the name. That is why people pick a name they actually want to keep.
Color this: write the name you would pick for your place. Say it out loud. Could a friend remember it tomorrow?
For the grown-up holding the crayon box:
Renting rather than owning is the accurate model and it is worth teaching correctly the first time. Registration is annual, it lapses, and a lapsed name with history attached is a real asset somebody else will pick up. That fact does more to explain digital property than any definition.