Unspent transaction output (UTXO) is a term used in blockchain technology to refer to a piece of information that identifies a specific amount of cryptocurrency that has been sent to a particular address and has not been spent yet. Each UTXO has a unique identifier and is associated with a specific address on the blockchain.

When a cryptocurrency transaction occurs, the funds are transferred from one address to another, and the amount of the transfer is recorded in the blockchain as a UTXO. The UTXO is then associated with the address that received the funds, and the transaction is considered complete.

UTXOs are an essential component of the blockchain ecosystem as they help to ensure the integrity and security of the network. The use of UTXOs allows for the tracking of individual units of cryptocurrency, making it easier to verify transactions and prevent fraud. Additionally, UTXOs help to facilitate faster and more efficient transactions on the blockchain, as they enable the creation of new transactions without requiring the need to reference the entire blockchain history.

Unspent Transaction Output (UTXO) is a key concept in blockchain, particularly in Bitcoin. It refers to the amount of cryptocurrency that remains after a transaction, which can then be used as input in a new transaction. Essentially, UTXOs function as a record of unused coins in a wallet, ensuring accurate tracking of balances.

When someone spends Bitcoin, the transaction's output becomes the UTXO, and each UTXO can only be spent once. This model enhances security and transparency by preventing double-spending. For example, if you receive 1 BTC and send 0.4 BTC to someone, the remaining 0.6 BTC becomes a new UTXO. This system differs from traditional accounts-based models, like in Ethereum, by treating transactions as distinct, spendable units.