Just out of curiosity, the Wiki says UTXO means "Unspent Transaction Output", but what does each letter mean in the acronym?


That seems to be a typo. Unspent transaction outputs are usually called UTXO's (Unspent TransaXtion Output).

  • "TX" in networking often stands for transmission (like "RX" often stands for receiving). I guess that's the origin of the term. A typo is not very likely. – Alfe Jun 20 '16 at 12:25
  • The typo is that the linked wiki article says "UXTO", not "UTXO". – Pieter Wuille Jun 20 '16 at 15:22

In the field of computer technology, the standard abbreviation for transaction is TX, and it is used elsewhere in Bitcoin as just that (for a single transaction) and in other combinations, for example TxIn meaning Transaction Input. (TX has a long history of being an abbreviation for "transaction", and before that "transmit" and related terms, but the exact origins of that abbreviation are unclear.) The U stands for Unspent and the O stands for Output, so the entire abbreviation for a single Unspent Transaction Output is UTXO.

Perhaps because TX is not an obvious abbreviation, perhaps because of dyslexia, perhaps because of the way people type on a QWERTY keyboard, UTXO is commonly miswritten as UXTO. However, the "official" Bitcoin glossary confirms that the proper abbreviation is UTXO.

UTXO does NOT stand for “Unspent Transaction Output Set”, which is the set of all UTXOs (UTXOs being the plural of UTXO). As far as I know, there is no common abbreviation for “Unspent Transaction Output Set” other than UTXO set.

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