The original full name was SEQUEL, which stood for "Structured English Query Language". It later had to be renamed to SQL due to trademark issues.
So basically, it was yet another attempt to sell a programming language as "just like English, except with a formal syntax" (hence "structured").
hope it clear your doubt, basically it was meant to have queries that everyone could read. The structured part means that you can only use a structured English; i.e. select col1 from table1, but not give col1 out of table1.
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Microsoft MVP 2014 [ASP.NET/IIS]