Capital B, small b
Bitcoin with a capital B is the network: the rules, the software and the nodes. bitcoin with a small b is the unit you send and receive. You send 0.01 bitcoin over the Bitcoin network.
The satoshi
One bitcoin divides into 100,000,000 smaller units called satoshis, or sats, named after Bitcoin's creator. A sat is the smallest amount the ledger can record.
- 1 bitcoin = 100,000,000 sats
- 0.001 bitcoin = 100,000 sats
- 1 sat = 0.00000001 bitcoin
So nobody needs to buy a whole bitcoin. You can own a few thousand sats, the price of a coffee, and they work exactly like any other bitcoin.
What Bitcoin is not
Bitcoin is not a company. It has no CEO, no office, no customer support. Nobody can reverse a payment you made by mistake or recover coins if you lose access to them. That is the price of a money nobody controls, and the next chapters will show you how to handle it safely.