amicus curiae

noun | \ -ˈkyu̇r-ē-ˌī, -ˈku̇r-, -ē-ˌē \ | amicus cu·ri·ae
  1. : one (as an individual or organization) that is not a party to a particular lawsuit but is allowed to advise the court regarding a point of law or fact directly concerning the lawsuit an amicus curiae must file its brief…no later than 7 days after the principal brief —Federal Rules of Appellate Procedure Rule 29 — called also friend of the court