Link equity
Link equity (sometimes called "link juice") refers to the value or authority passed from one webpage to another through hyperlinks. This value is a key factor in determining how search engines rank pages in their results.
When a page links to another, it passes some of its link equity to the linked page. This can boost the linked page's SEO, making it more likely to rank higher in SERP. For example, a website with high domain authority or page authority linking to your page transfers more link equity than a low-authority site.
301 redirects help preserve link equity when URLs change. For instance, if a page's URL structure changes during a website redesign, implementing a 301 redirect ensures the link equity from the old URL is passed to the new one.
Internal links within your website architecture also distribute link equity across pages. For example, linking from a high-performing blog post to a less-visited page can improve the latter's visibility.
External links play a role in link equity too. Links from reputable sites carry more value than those from spammy or low-quality sources. However, nofollow links do not pass link equity, as they tell web crawlers not to follow them.