[n] an adviser to the court on some matter of law who is not a party to the case; usually someone who wants to influence the outcome of a lawsuit involving matters of wide public interest
friend of the court
advocate, agent, alter ego, alternate, assessor, attorney, attorney-at-law, backup, backup man, barmaster, barrister, barrister-at-law, champion, chancellor, circuit judge, counsel, counselor, counselor-at-law, deputy, dummy, executive officer, exponent,