Google Juice is a slang term used within the SEO and advertising community to refer to the beneficial ranking impact of one page passing to another. For instance, if a page from a reputable news organisation links to another webpage, the news organisation is passing Google Juice to the webpage it’s linking to.
In essence, this slang term is shorthand for the positive impact on page rank of certain links between webpages on the internet. The more positive associations that can be built, the better it is for a webpage’s search engine ranking.