DNS Prefetching is the process used by your browser to execute DNS Lookups for links on the page, in the background, while you're browsing the current page.
As a result, when you finally click on a link for which DNS Prefetch has been performed, you'll experience a faster response because the DNS Lookup has already been performed (otherwise, the lookup will only trigger after you click the link).
DNS Prefetch is specified for the resources to which links are pointing by specifying target addresses in link tags, such as:
<link rel="dns-prefetch" href="https://gilad-ehven.com" />
DNS Prefetching is well supported in modern browsers, and many web publishing platforms can generate the required link tags automatically.