In the word "NoSQL", the letters "No" are an acronym so the meaning is "Not Only SQL" rather than "No SQL". True or false?
The first NoSQL product was a classic DBMS which didn't happen to use SQL for a query language, featured in Linux Journal in 1999. Its current web page has a traffic-sign symbol of the word SQL with a bar through it, and a title "NoSQL: a non-SQL RDBMS".
For a meetup in June 2009 about "open source, distributed, non-relational databases" the question came up "What's a good name?" Eric Evans of Rackspace suggested NoSQL, a suggestion which he later regretted.
In October 2009 Emil Eifrem of NeoTechnology tweeted "I for one have tried REALLY HARD to emphasize that #nosql = Not Only SQL". This appears to be the earliest recorded occurrence of the suggestion. In November 2009 Mr Eifrem declared with satisfaction that the suggestion was "finally catching on".
In other words saying "No = Not Only" is an example of a backronym, and specifically it's a class of backronym known as False Acronyms. There are lots of these around -- like the idea that "cabal" stands for seventeenth-century English ministers named Clifford Arlington Buckingham Ashley and Lauderdale, or the myth that "posh" means "port out starboard home". False acronyms might go back at least 1600 years, if the earliest example is the "Jesus Fish". Anyway, backronyms are popular and fun, but this one's false.
Regardless of etymology, NoSQL could currently mean Not Only SQL, if everyone accepted that. So, getting the new interpretation going is a matter of evangelism -- tell everyone that's what it means, and hope that they'll tell their friends. Is that working?
I think it has worked among NoSQL insiders, but it's tenuous. If it were generally believed, then the common spelling would be NOSQL rather than NoSQL, and the common pronunciation would be "En O Ess Cue Ell" rather than "No Sequel". Although my sample size is small, I can say that I've rarely seen that spelling and I've rarely heard that pronunciation.
And the general public knows that "no-starch" products don't contain more than starch, or that "no-goodniks" are in a class beyond goodness, and that the slogan "No means no!" is a response to proponents of sexual assaults. So, when confronted with the claim that no doesn't mean no, there's inevitable resistance or disgust.
It would still be okay to promote the idea that "NoSQL" equals "not only SQL" if the term described a group of products that are (a) SQL and (b) something other than SQL. This is where, in a rephrasing of the Wendy's "Where's The Beef?" commercial, the first question is: "Where's the SQL?"
Back in 2009 the answers would have been pathetic, but nowadays there are "SQL" query languages that come from NoSQL vendors. CQL would qualify as an SQL product if the bar was low, like saying "If it MOVEs, it's COBOL". Impala would qualify in a more serious way, in fact most of the core-SQL tick-box items are tickable. (I'm believing the manual, I didn't do vicious testing as I did with MySQL.) So, although they're a minority, there seem to be NoSQL vendors who supply SQL.
But the second question is: what can these products do that can't be done in SQL? Well, they can supply language extensions, and they can allow the SQL layer to be bypassed. However, so can MySQL or MariaDB -- think of the navigation with HANDLER or direct access with HandlerSocket. In that case MySQL would be a NoSQL DBMS, and if that were true then the term NoSQL wouldn't distinguish the traditional from the non-traditional products, and so it would be a useless word.
Therefore pretending that NoSQL means Not Only SQL is wrong in several ways, but insisting it still means No SQL is merciless. Perhaps an honest solution is to stop saying that the word's parts mean anything. It's just a name now, in the same way that "PostgreSQL" is just a name and you've forgotten what's it's a post of.