When is a page not a page? When the page is a story, a blog entry, etc.

When is a story not a story? When the story is a page, a forum topic, etc.

And so on. Did that make sense to you? If so, you've made the effort to absorb Drupal's self-referential terminology, and can quickly parse a word like "page" to mean a generic web page or a specific type of Drupal node, as context dictates.