Cryptocurrency has a somewhat related naming convention backstory. Here’s is how David Schwartz, Chief Cryptographer at Ripple, sheds light on Ripple’s XRP naming convention a couple of months ago.
Three-letter currency codes are formed by appending a single character to the two-letter country code of the issuing country. Since the United States’ country code is “US”, US dollars have the currency code “USD”. Some non-countries still have country codes. The EU has the country code “EU”, so the currency code for Euros is “EUR”.
Of course, XRP is not issued by any country. For assets not issued by any country, the first letter must be X. No country codes starting with X will be issue. So, for example, since the chemical symbol for gold is Au, gold’s currency code is XAU.
Some people use “BTC” for bitcoin, but people who care about standards use “XBT”. XRP’s first letter is X because XRP is not issued by any country.
In the early days, we called the ledger’s native asset “ripples”. So the natural currency code to choose was “XRP”. I don’t think anybody calls them “ripples” any more, but I have heard “zerps”.
There you go. Probably not something you need to know, but as cryptocurrency gains more broad acceptance, questions like this one will pop up which you can now answer! I admit I used to refer to bitcoin as BTC. After looking up XRP’s naming convention, I’ll now start to use the one based on a standard.