Bitcoin is a digital and global money system currency. It allows people to send or recieve money across the internet, even to someone they don't know or don't trust. Money can be exchanged without being linked to a real identity. The mathematical field of cryptography is the basis for Bitcoin's security.

Transactions are made by sharing public passwords attached to a private and encrypted digital wallet. Each password relates back to a “block” of transactions on a digital ledger (called a blockchain) and represents X amount of digital coins.

All maths and technical jargon aside, that is the gist of every cryptocurrency from bitcoin to litecoin (although a few cryptocurrencies don’t use a blockchain and many have some unique mechanics).