<p>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. </p>

<p>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 <em>miswritten</em> as <em>UXTO</em>. However, the "official" <a href="https://bitcoin.org/en/glossary/unspent-transaction-output" rel="nofollow noreferrer">Bitcoin glossary confirms</a> that the proper abbreviation is UTXO.</p>

<p>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 <strong>UTXO set</strong>.</p>

CC BY-SA 3.0
2017-11-27T20:41:55.617Z
2017-11-27T20:41:55.617Z
Old Pro
<p>That seems to be a typo. Unspent transaction outputs are usually called UTXO's (Unspent TransaXtion Output).</p>

CC BY-SA 3.0
2016-06-20T12:25:42.117Z
"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
CC BY-SA 3.0
2016-06-20T15:22:43.593Z
The typo is that the linked wiki article says "UXTO", not "UTXO".
Pieter Wuille
CC BY-SA 4.0
2023-10-30T13:44:26.677Z
Fixed the typo in the wiki.
Murch
CC BY-SA 3.0
2014-03-08T00:06:13.473Z
2014-03-08T00:06:13.473Z
Pieter Wuille
<p>Just out of curiosity, the <a href="https://en.bitcoin.it/wiki/Weaknesses#Denial_of_Service_.28DoS.29_attacks" rel="nofollow noreferrer">Wiki</a> says <code>UTXO</code> means "Unspent Transaction Output", but what does each letter mean in the acronym?</p>

<utxo><terminology><bitcoin-wiki>
Why the "Unspent Transaction Output Set" is called "UTXO", not "UTOS"?
Ning
# Why the "Unspent Transaction Output Set" is called "UTXO", not "UTOS"?

(Asked by: username_0 on 2014-03-06)

Just out of curiosity, the [Wiki](https://en.bitcoin.it/wiki/Weaknesses#Denial_of_Service_.28DoS.29_attacks) says `UTXO` means "Unspent Transaction Output", but what does each letter mean in the acronym?

**Tags:** utxo, terminology, bitcoin-wiki


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## 2 answers

### Answer by username_2 on 2014-03-08. Score: 8 | Accepted answer

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

> **Comments:**
> **username_3**: "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.  
> **username_2**: The typo is that the linked wiki article says "UXTO", not "UTXO".  
> **username_4**: Fixed the typo in the wiki.  

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### Answer by username_1 on 2017-11-27. Score: 1

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](https://bitcoin.org/en/glossary/unspent-transaction-output) 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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