In the government

Government

Government refers to the legislators, administrators, and arbitrators in the administrative bureaucracy who control a state at a given time, and to the system of government by which they are organized...

, bicameralism (Latin , two + , chamber) is the practice of having two legislative or parliamentary chambers. Thus, a bicameral parliament or bicameral legislature is a legislature

Legislature

A legislature is a kind of deliberative assembly with the power to pass, amend, and repeal laws. The law created by a legislature is called legislation or statutory law. In addition to enacting laws, legislatures usually have exclusive authority to raise or lower taxes and adopt the budget and...

 which consists of two chambers or houses.

Bicameralism is an essential and defining feature of the classical

Classical antiquity

Classical antiquity is a broad term for a long period of cultural history centered on the Mediterranean Sea, comprising the interlocking civilizations of ancient Greece and ancient Rome, collectively known as the Greco-Roman world...

 notion of mixed government

Mixed government

Mixed government, also known as a mixed constitution, is a form of government that integrates elements of democracy, aristocracy, and monarchy. In a mixed government, some issues are decided by the majority of the people, some other issues by few, and some other issues by a single person...

. Bicameral legislatures tend to require a concurrent majority

Concurrent majority

Concurrent majority refers in general to the concept of preventing majorities from oppressing minorities by allowing various minority groups veto power over laws. The most vocal proponents of the theory have tended to be minority groups, such as farmers in an industrial society or nonwhites in a...

 to pass legislation.
Although the ideas on which bicameralism is based can be traced back to the theories developed in Ancient Sumer

Sumer

Sumer was a civilization and historical region in southern Mesopotamia, modern Iraq during the Chalcolithic and Early Bronze Age....

 and later ancient Greece

Ancient Greece

Ancient Greece is a civilization belonging to a period of Greek history that lasted from the Archaic period of the 8th to 6th centuries BC to the end of antiquity. Immediately following this period was the beginning of the Early Middle Ages and the Byzantine era. Included in Ancient Greece is the...

, ancient India

History of India

The history of India begins with evidence of human activity of Homo sapiens as long as 75,000 years ago, or with earlier hominids including Homo erectus from about 500,000 years ago. The Indus Valley Civilization, which spread and flourished in the northwestern part of the Indian subcontinent from...

, and Rome

Ancient Rome

Ancient Rome was a thriving civilization that grew on the Italian Peninsula as early as the 8th century BC. Located along the Mediterranean Sea and centered on the city of Rome, it expanded to one of the largest empires in the ancient world....

, recognizable bicameral institutions first arose in medieval Europe where they were associated with separate representation of different estates of the realm.