The part of government which is concerned with making of rules

One word substitute is Legislature.

Court: a body of people presided over by a judge, judges, or magistrate, and acting as a tribunal in civil and criminal cases.
Tribunal: a body established to settle certain types of dispute.
Bar: a counter in a pub, restaurant, or cafe across which drinks or refreshments are served.
Legislature: the part of government which is concerned with making of rules.