I think you may be referring to "link juice". SEO juice isn't a term I've ever encountered. Maybe it is something else, I don't know.
But link juice is usually considered to be the Google PageRank that is awarded to a web page as a result of being linked from another web page. The "SEO" notion is that having many links pointing to a web page flows more Google Page Rank value to that webpage and that this, this moving of green googlebar puke from one linked-up dumping fountain to the open-mouthed masses of content mediocrities somehow over time has managed to create a global illusion that web pages will rank better because of it.
don't read this
Just for clarification (and a shot at the grey hats), being good at link juicing web pages is not the same thing as being able to perform SEO (search engine optimisation) well. Note: good (effective white hat) SEO doesn't derive from off-site/off-page activities (that's basically all artificial link building including link juicing SEO techniques).
A page which has lots of links that we called that it has good link juice
Actually, those websites displayed on that page get just a little link juice, as they have to share it. If your link is displayed on a website containing a total of 3 links, you get more link juice (and that's better) than displaying your link on a website with tons of other links.