Juice is the term used for how much benefit a link passes on, as not all links are equal.
A link is assumed to pass more link juice if
1. it does not have the no-follow attribute added
2. the page the link is on is indexed by the search engines
3. the number of links on the page that the link is on are low
4. a page with a higher mozRank and mozTrust is likly to pass more link juice