It means “friend of the court”. The person is not a party to the case in any manner. His sole purpose is to assist the court by providing substantial information or insight for the smooth disposal of the case.
A legal custom is the established pattern of behaviour which will be objectively verified within a specific social setting.
This is a doctrine in the law of tort where a court infers negligence from the nature of the accident or the injury in absence of any direct evidence on how the defendant behaved.
“things to be done”.
