One of WordPress's biggest flaws is its imprecise vocabulary. Many otherwise simple concepts are made complex by inaccurate or conflicting terms. Later in this book, watch out for this problem with:

Hooks, actions, and filters
Custom fields and "post meta"
Widget areas and "sidebars"
Featured images and "thumbnails"
"Nav menus" and "nav menu areas"

This chapter examines the two terms that are the worst offenders of all: "posts" and "pages." We'll break down the various possible uses of those terms in a WordPress context, and what they mean.
Diagram
Let's get started with a visual diagram of the topic:

We'll explain this through the rest of the chapter.
A Webpage is an HTML Document
All "webpages" are HTML documents being served to your web browser.
The first way people use the word "page" is to refer to a webpage, as in: "I've got Firefox open and I'm looking at...