Define Bitcoin for me

I want you to define bitcoin for me so i can send this thread to my friend because he thinks that bitcoins are handheld physical items. I would like you, people of the internet to prove him wrong so he can finally shut up.

What's the point of this?
Why would he take our word over the many available and reliable resources about bitcoin and other crypto currencies?

https://en.wikipedia.org/wiki/Bitcoin
https://en.wikipedia.org/wiki/Cryptocurrency

"A cryptocurrency (or crypto currency) is a digital asset designed to work as a medium of exchange that uses cryptography to secure its transactions, to control the creation of additional units, and to verify the transfer of assets."

its a currency and u can hold it in ur hand if u buy a physical note of it like this



see??