Who named bitcoin's smallest unit the satoshi: a 2011 forum nickname, an "Affirmative," and the Oxford English Dictionary

On January 9, 2014, a newcomer to BitcoinTalk asked where a name came from. Bitcoin’s base unit, one hundred millionth of a coin, is called a satoshi. Why? “Did Satoshi decided this name, or others started using it in their honor?” Thirty minutes later a user named ribuck answered:

Rribuck (BitcoinTalk post, January 09, 2014, 8:49:00 PM UTC)

I was the one who proposed the name satoshi.

He gave dates, linked his old posts, named the post where he thought the usage caught on, and ended with a sentence about Satoshi himself. Every claim in that answer can be checked against the forum record, and the record is more crowded than his four paragraphs. The name went through four threads, three different sizes, and a rival scheme that the project’s lead developer gave a “+1.” Satoshi wrote in none of those threads.

1. What Satoshi left without a name

Satoshi’s code named two amounts. In Bitcoin v0.1, main.h sets COIN = 100000000 and CENT = 1000000: a coin is one hundred million base units, a cent is a hundredth of a coin. The base unit itself has no name in the source. The client printed amounts to two decimal places and refused anything finer, so the smallest amount a user could see or type was one cent, and the page on Satoshi’s cents follows that unit through his code, fees and emails. The six digits below it were there from the start and hidden from the start.

Satoshi’s plan for a coin that grew too valuable was to move the decimal point, not to name anything smaller. He wrote:

SNSatoshi Nakamoto (email to Mike Hearn, January 10, 2011, 4:34:00 PM UTC)

If it gets really big, the decimal can move two places and cents become the new coins.

Satoshi’s own writing in this archive never gives the hundred-millionth a name. His last forum post is dated December 12, 2010. Every naming debate below happened after it.

2. November 2010: a satoshi was a cent

The earliest use of the name in this record is a proposal for a different amount. On November 15, 2010, in a thread about a currency symbol, nine months after NewLibertyStandard had proposed ฿ and the code BTC, ribuck wondered how bitcoin would be subdivided, and offered names: “A hundredth of a bitcoin could be a Satoshi, a thousandth of that could be a Molyneau, and a thousandth of that could be an Austrian.”

The first satoshi, then, was 0.01 BTC: the cent that Satoshi’s own client already treated as the floor. ribuck’s 2014 account explains the choice the same way, “At the time, 0.01 BTC was the smallest unit that could be displayed by the user interface in the standard client.”

3. February 10, 2011: the bitcent thread

Three months later the price did what the forum had been half expecting. On February 10, 2011, goblin opened a thread titled “More divisibility required - move the decimal point”: “one bitcent is now worth more than the american currency’s lowest divisible unit - cent.” Within three hours the people who ran the project had joined in.

Mike Hearn’s reply opened with the fact that set the terms for everything after:

MHMike Hearn (BitcoinTalk post, February 10, 2011, 4:09:15 PM UTC)

It’s easy to say “let’s just move the decimal point”. But this part of BitCoin is unusual in that it has not been well thought out by Satoshi in advance. Given he is absent, I guess it’s up to us to come up with a good plan.

Hearn’s plan was a miner vote on where the decimal point should sit. Gavin Andresen, who had announced in December that he would manage the project with Satoshi’s blessing, cut the thread in two: the next release should simply show and send every digit, and the fee rules built around 0.01 BTC were a separate question. “It is too early to be worried about ‘paying 0.001 bitcoins for a pair of socks’.”

Between those two posts, ribuck proposed a vocabulary instead of a mechanism:

Rribuck (BitcoinTalk post, February 10, 2011, 4:53:35 PM UTC)

One bitcoin equals 100 bitcents
One bitcent equals one thousand millicents
One bitcent equals one million microcents

By subdividing the bitcent rather than the bitcoin, we neatly end up with a name for the tiniest piece of bitdust, i.e. 1/100000000 of a bitcoin.

No doubt in time nicknames would arise for these small units. I like “austrian” and “satoshi” as possible nicknames

In three months the satoshi had shrunk by a factor of a million, from the cent to the microcent, and it was still only a nickname. Hal Finney liked the bitcent half of the proposal and said so. The next day jon_smark liked the other half and moved it the opposite way. Mixing steps of a hundred with steps of a thousand would confuse people, he wrote; “Satoshi” was a good candidate, “Austrian” was not, and the units should run in thousands: “1 satoshi = 1000 BTC”, then 1,000 koishi to the bitcoin and 1,000 suna to the koishi, from the Japanese words for pebble and sand. For one day, the satoshi was the largest unit on offer. That one made me laugh.

4. February 18, 2011: “Are we agreed?”

A week later Kolbas started a new thread with the same worry and one word for a title, “Bitcent?” Hal Finney pointed it back to ribuck’s terms, noting that the microcent was exactly the smallest unit the software could hold. Three hours after that, kiba wrote: “I can’t wait to use satoshi to denote a very small fraction of bitcoin.” Then marcus_of_augustus, whose posts were quoted at the time under the name moa, wrote three lines:

Mmarcus_of_augustus (BitcoinTalk post, February 18, 2011, 8:50:57 AM UTC)

1 satoshi = 1 microbitcent (smallest denomination)

100 million satoshis = 1 bitcoin

Are we agreed?

Two hours later one reply answered the question:

NTno to the gold cult (BitcoinTalk post, February 18, 2011, 10:51:26 AM UTC)

Affirmative.

That is the whole agreement in the record: a question from one user and a one-word answer from another, in a thread of nineteen posts that day. The account that answered now displays the name “no to the gold cult”; posts quoting it later that day show it as SumChancer. When ribuck told the story in 2014, this was the exchange he credited: marcus_of_augustus asked, “someone responded ‘affirmative’, and the usage caught on.”

5. Spring 2011: nothing official

Agreement in one thread settled nothing outside it. Between November 2010 and May 2011, the same word was given three different sizes.

In April, marcus_of_augustus argued that the easiest way out was “to give a name, any name, to the smallest denomination” and count upward, and bet “100 million sts” that it would work out that way. In May, when tardo asked whether bitcent was the official term for a hundredth of a bitcoin, ribuck listed his units and answered in four words: “Nothing is official.” The same afternoon jon_smark argued against the bitcent altogether, for millicoins, microcoins and nanocoins counted in thousands, and Gavin Andresen replied “+1”. The lead developer’s one vote in these threads went to the metric prefixes.

The first unit selector in the software used the same prefixes: in July 2011, Wladimir van der Laan prepared the new graphical client to show amounts in BTC, mBTC or uBTC. The Bitcoin Wiki’s Units page, first written by Luke-jr on January 16, 2011, a month before the bitcent thread, tabulated decimal and Tonal units and had no satoshi in it. The wiki page “Satoshi (unit)” was a redirect to Satoshi Nakamoto’s biography until June 12, 2013, when someone gave it a first sentence: the smallest unit, “named ‘satoshi’ in collective homage to the founder.”

6. From nickname to unit

The word made its way into software and specifications years after the forum had settled on it.

The Lightning Network’s specification, drafted from 2016, counts payments in millisatoshi, thousandths of a satoshi, an amount the Bitcoin blockchain itself cannot record. BIP 176, assigned in December 2017, proposed the “bit” for a millionth of a bitcoin and defined it as “1 bit = 100 satoshis.” In May 2018 a contributor named GreatSock added “Satoshi (sat)” to the units the Bitcoin Core wallet could display; it shipped in version 0.17 that October. Version 0.21, released in January 2021, added fee-rate options to Bitcoin Core’s commands “denominated in satoshis per vbyte (sat/vB).” The unit that Satoshi’s code had left unnamed was now the unit that fees were quoted in.

7. The dictionaries

The Oxford English Dictionary added satoshi in its October 2019 update: “The smallest monetary unit in the Bitcoin digital payment system, equal to one hundred millionth of a bitcoin.” The entry gives its etymology as Satoshi Nakamoto’s name and dates its earliest evidence to 2012. Every forum post above comes before 2012. The dictionary’s date is the earliest example it cites, not the day the word was coined.

Two of the five list the word. Merriam-Webster and Dictionary.com, the American dictionaries checked here, do not, and neither does Cambridge.

8. ribuck’s account, checked

ribuck’s 2014 answer holds up against the record. He did propose the name, twice, first for 0.01 BTC and then for the base unit; the second proposal was a nickname inside a bitcent scheme, as he said; and the February 18 exchange he credited happened as he described it. His last sentence is the one the record does not bear out:

Rribuck (BitcoinTalk post, January 09, 2014, 8:49:00 PM UTC)

Satoshi Nakamoto referred to the base unit simply as a “coin” in his writings.

In Satoshi’s code, COIN is the whole bitcoin, one hundred million base units, and his writing in this archive does not call the base unit anything. When Satoshi wanted something smaller than a coin, he said cent.

Below the coin, the only unit Satoshi ever named was the cent, and he planned to retire it by moving the decimal point. The name on the smallest piece of his currency was chosen without him, in a thread where an early reply noted he was gone and in another that settled it with one word from an account that has since changed its name. I find something right in that. The name that now carries Satoshi into every fee quote, in sats per vbyte, is a word he never wrote.