Circle is a type of administrative division of some countries. In Thailand the former monthon are translated as circle. In German it is called Kreis; the former Holy Roman Empire was organized into Imperial Circles. Algerian daïras are circles.

A circle is a simple shape of Euclidean geometry consisting of those points in a plane that are equidistant from a given point, the centre. The distance between any of the points and the centre is called the radius.

Circles are simple closed curves which divide the plane into two regions: an interior and an exterior. In everyday use, the term "circle" may be used interchangeably to refer to either the boundary of the figure, or to the whole figure including its interior; in strict technical usage, the circle is the former and the latter is called a disk.

A circle can be defined as the curve traced out by a point that moves so that its distance from a given point is constant.

A circle may also be defined as a special ellipse in which the two foci are coincident and the eccentricity is 0. Circles are conic sections attained when a right circular cone is intersected by a plane perpendicular to the axis of the cone.

A circle's diameter is the length of a line segment whose endpoints lie on the circle and which passes through the centre. This is the largest distance between any two points on the circle. The diameter of a circle is twice the radius, or distance from the centre to the circle's boundary. The terms "diameter" and "radius" also refer to the line segments which fit these descriptions. The circumference is the distance around the outside of a circle.

An administrative division, subnational entity, or country subdivision is a portion of a country or other political division, established for the purpose of government. Administrative divisions are each granted a certain degree of autonomy, and are required to manage themselves through their own local governments. Countries are divided up into these smaller units to make managing their land and the affairs of their people easier. For example, a country may be divided into provinces, which in turn are divided into counties, which in turn may be divided in whole or in part into municipalities. These are only a few of the names given to administrative subdivisions; more examples are provided below.

Administrative divisions are conceptually separate from dependent territories, with the former being an integral part of the state and the other being only under some lesser form of control. However, the term "administrative division" can include dependent territories as well as accepted administrative divisions (for example, in geographical databases).

A country is a region legally identified as a distinct entity in political geography. A country may be an independent sovereign state or one that is occupied by another state, as a non-sovereign or formerly sovereign political division, or a geographic region associated with sets of previously independent or differently associated peoples with distinct political characteristics. Regardless of the physical geography, in the modern internationally accepted legal definition as defined by the League of Nations in 1937 and reaffirmed by the United Nations in 1945, a resident of a country is subject to the independent exercise of legal jurisdiction.

Sometimes the word country is used to refer both to sovereign states and to other political entities, while other times it refers only to states. For example, the CIA World Factbook uses the word in its "Country name" field to refer to "a wide variety of dependencies, areas of special sovereignty, uninhabited islands, and other entities in addition to the traditional countries or independent states".

Subdivision may refer to: