Your bitcoin is on a single (financial) ledger that is distributed all over the world. Any device that has a copy of this ledger is called a node. A ledger provides a record of each debit and credit transaction across the lifespan of bitcoin. Each transaction documented and ‘mined’ in a block of transansactions within the ledger. The way these blocks are created is very special because it links each block of transactions with the previous block creating a linked chain. This is why it is called a blockchain. Your bitcoin never leaves the blockchain; only entries in the ledger are created that tell everyone that specific bitcoin has moved from the sender to the receiver. This special method of linking the previous block to the next block prevents the double-spend scenario (meaning you can’t spend the same bitcoin twice).
