Link Juice is nothing but the link equity that a link passes to another. It can be passed to your website from an external link or even from one internal webpage to the other.

It is a well-known fact that every link that points towards your website is considered as a vote of recommendation towards your site by Google. Votes from sites with a strong link equity are considered as a stronger recommendation for your website.

Link juice refers to the benefits of the ranking factors which gets passed on from one link to the other.