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I'm still unsure when to use Bitcoin and when bitcoin is more appropriate. Did anyone define when to use the word Bitcoin with a capital B? Is one used to talk about the currency as in "3 Bitcoin" and the other for the "bitcoin protocol"?

marked as duplicate by Murch, Stéphane Gimenez, Salvador Dali, dchapes, John T Feb 4 '14 at 5:49

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From Introduction on the Bitcoin wiki:

Capitalization / Nomenclature

Since Bitcoin is both a currency and a protocol, capitalization can be confusing. Accepted practice is to use Bitcoin (singular with an upper case letter B) to label the protocol, software, and community, and bitcoins (with a lower case b) to label units of the currency.

So, the accepted usage in your example would be "3 bitcoin" and the "Bitcoin protocol".

  • So "add the bitcoin amount" with small b is correct as we talk about the units of the currency? Thanks. – Cimm Mar 25 '14 at 8:54
  • @Greg, So would we say "I have a bitcoin address" or "I have a Bitcoin address"? – Pacerier Jun 2 '14 at 9:20
  • @Pacerier: According to the above, that would be "Bitcoin address". – Greg Hewgill Jun 2 '14 at 16:09

Bitcoin (capital B) is the name of a currency, a technology, and a movement. A bitcoin (small b) is a unit of this currency.

Example: "After hearing about Bitcoin, I've installed a Bitcoin client and bought 3 bitcoins."

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