$elementxero = 'correct';
You pronounce it "Sequel." It stands for Structured Query Language.
Basically a language that calls data from a database.
For example:
SELECT * FROM refrigerator WHERE type = 'fruit'
In literal terms this would tell you to grab all the fruit from your refrigerator.
This forum uses SQL, imagine if you had to manually create every page on this forum.
When you come to this page it performs a huge number of sql queries.
Tells the server to display all all posts in the database that is related to this topic, for example.
Much more complex, but maybe that will clear things up a bit.