What is above-the-fold content?

Question

According to the "About" page of Google PageSpeed Insights the test measures:

• time to above-the-fold load: Elapsed time from the moment a user requests a new page and to the moment the above-the-fold content is rendered by the browser.
• time to full page load: Elapsed time from the moment a user requests a new page to the moment the page is fully rendered by the browser.

I'm not a native English speaker, so the "above-the-fold" load sounds strange to me, especially as the same "above-the-fold" is used even in the definition and nothing else is described in there.

So, what's meant by the special "above-the-fold content" i.e. what files and/or what elements of the page are in this category and how is it different from the full page load time?

Answer 1

http://www.whereisthefold.com/ states:

The fold is a term used by webmasters and website owners to mean the portion of your site which can be shown when first entering the site without scrolling down at all.

Therefore, above the fold means everything that is shown on the first screen page. So if your web browser page window is 1000 pixels wide and 800 pixels down then anything that can fit in that without the need to scroll down is above the fold.

Think of fold as a first page-break.

Also, google thinks of content as user visible text, so any characters you see on the screen without scrolling is above the fold. If your page started with a large image that's bigger than almost everyone's screen size and your HTML instructed the browser to start text underneath the image, then the content for the affected users is then below the fold.