UTXO stands for “Unspent Transaction Output”. In cryptocurrencies, a UTXO is an abstraction of electronic money. Each UTXO is analogous to a coin, and holds a certain amount of value in its respective currency.
Another way to look at it, using a fiat money analogy, is that UTXOs represent various amounts of “change” available to any particular user. The unspent values in each block are UTXOs, and when they are “spent” (used in a transaction) they create new “change” (new UTXOs). Detailed information.