Preload

Definitions

To force the browser or runtime to fetch a critical resource at high priority early in the page lifecycle, before the parser would naturally discover it. In HTML, link rel="preload" tells the browser to immediately begin downloading a font, script, or image that is needed for the current page.
In plain English: Telling the browser to start downloading an important file right away instead of waiting until it stumbles across the need for it.
Example: "We preload the hero image and the web font so the above-the-fold render doesn't flash unstyled text."