Very basic understanding of Drupal and how it works

Nancy had a few suggested changes, some of which I agreed with, and I've also made others. Take a look and see if you feel anything else needs adjusting.

An over simplification of what Drupal is helping to create. This is non-technical, and isn't about the actual mechanics.

Drupal provides a engine to show content and a way to hold that content.

How the content is held is based on tables, which are part of a database. When content is created the pieces are put into tables inside this database.

Data is actually contained in various tables and cross applied creating a complex database in which to query from. (This database is actually created prior to starting your Drupal installation.)

Information can be retrieved out of this table in a number of ways including:
Content Type (Page, story, blog, book), Content Title (Title given when it's created), & Taxonomy (Category>Vocabulary>Term).

Having different content types allows for groupings, a way to effect the appearance, and define who has access to it, so in a sense they are like another way to tag an item. It gives the display engine a way to retrieve the data, tell it how it should be laid out, and who can see it.

Titles & Taxonomy allow for the same.

How the content is seen is based on the display engine (Theme, blocks, and all that php stuff).

Nothing exists anywhere as a page of information, like in a book, or on a static web site, but is created as a page by the display engine.

For simplicity this is a basic idea of what is happening.

Heading:
Content Type - Content Title - Taxonomy - Content
_{Items in bold can be pulled from to create the view}

Data:
Story - Mary had a little Lamb - Child, lamb - Mary had a little lamb whose fleece was white as snow.
Story - Jack and the Bean Stalk - Child, beans - There once was a boy named Jack...
Page - What you need to know about beans - Information, beans - Beans can be a great source of protein, but you need to know the type...

The display engine can be told to display all Content Types, or Titles, or Taxonomy Terms as links to the data. These links are something like a search where you search based on one of those Headings and the display engine presents you with the data that includes the "type" you clicked on, retrieving it from the table (database) showing you what exists in that row (what data fits the query).

If you were looking for what types of content existed, the display engine based on the question (query) would be able to present:
Story
Page
These would be links because they are main data types that can be retrieved and queried.

When you click on an individual link presented in that search or query the display engine then is directed to show only the data that exists for that specific heading type. Displayed again how it was told to display it.
Stories:
Mary had a little Lamb
Jack and the Bean Stalk

And then the display engine could be told how to display a single view of a single story:

Mary had a little Lamb(title)           Child Lamb (terms)
Mary had a little lamb who's fleece was white as snow (content)

Without the display engine the content wouldn't have design or meaning, without the database there wouldn't be a way to organize, retrieve or find the information in a multitude of ways. Together they give you the ability to effect both what you see and how it looks.