Why blockchain matters to a first-time founder
A blockchain is a shared history of records. Entries are grouped into blocks, and each new block links to the one before it, so the record is meant to be append-only. Several organisations can hold the same history. That does not make the record a currency, replace a contract, or prove that the facts typed in at the start were true.
Examples of blockchain
A trading firm in Singapore and its freight partners write each handover of a shipment to a permissioned blockchain. Each party can read the same sequence, and a new entry does not wipe an old one. The goods are paid for in Singapore dollars through a bank. No cryptocurrency is used. A wrong weight entered at the warehouse stays wrong. The chain keeps the entry. It does not weigh the goods.
Common misunderstanding
A blockchain is not a cryptocurrency and not a coin. Public networks, including the one Bitcoin uses, are one design. Private chains have a known set of participants and someone who administers access. Immutable, in this setting, names the aim of making quiet rewrites hard. Forks, software faults, and the administrator of a private chain can still change what the record becomes.
When to use it
Use the word when several organisations need one append-only history and do not want a single member to be the only record-keeper. For your own books, an ordinary ledger is usually the right tool. Ask who may add entries, who pays to run the system, and what happens when the input is wrong.