A crown prince or crown princess is the heir or heiress apparent

Heir apparent

An heir apparent or heiress apparent is a person who is first in line of succession and cannot be displaced from inheriting, except by a change in the rules of succession....

 to the throne

Throne

A throne is the official chair or seat upon which a monarch is seated on state or ceremonial occasions. "Throne" in an abstract sense can also refer to the monarchy or the Crown itself, an instance of metonymy, and is also used in many expressions such as "the power behind the...

 in a royal or imperial monarchy

Monarchy

A monarchy is a form of government in which the office of head of state is usually held until death or abdication and is often hereditary and includes a royal house. In some cases, the monarch is elected...

. The wife of a crown prince is also titled crown princess.

The term is now borne as a title

Title

A title is a prefix or suffix added to someone's name to signify either veneration, an official position or a professional or academic qualification. In some languages, titles may even be inserted between a first and last name...

 only in Thailand

Thailand

Thailand , officially the Kingdom of Thailand , formerly known as Siam , is a country located at the centre of the Indochina peninsula and Southeast Asia. It is bordered to the north by Burma and Laos, to the east by Laos and Cambodia, to the south by the Gulf of Thailand and Malaysia, and to the...

 and the Scandinavia

Scandinavia

Scandinavia is a cultural, historical and ethno-linguistic region in northern Europe that includes the three kingdoms of Denmark, Norway and Sweden, characterized by their common ethno-cultural heritage and language. Modern Norway and Sweden proper are situated on the Scandinavian Peninsula,...

n monarchies; but it may also be used generically to refer to the person or position of the heir apparent in other kingdom

Monarchy

A monarchy is a form of government in which the office of head of state is usually held until death or abdication and is often hereditary and includes a royal house. In some cases, the monarch is elected...

s. However, heirs apparent to non-imperial and non-royal monarchies (i.e., wherein the hereditary sovereign holds a title below that of king/queen, e.g., grand duke

Grand Duke

The title grand duke is used in Western Europe and particularly in Germanic countries for provincial sovereigns. Grand duke is of a protocolary rank below a king but higher than a sovereign duke. Grand duke is also the usual and established translation of grand prince in languages which do not...

 or prince

Prince

Prince is a general term for a ruler, monarch or member of a monarch's or former monarch's family, and is a hereditary title in the nobility of some European states. The feminine equivalent is a princess...

), crown prince is not used as a title, although it is sometimes used as a synonym for heir apparent.

In Europe, where primogeniture

Primogeniture

Primogeniture is the right, by law or custom, of the firstborn to inherit the entire estate, to the exclusion of younger siblings . Historically, the term implied male primogeniture, to the exclusion of females...

 governs succession to all monarchies except those of the Papacy

Pope

The Pope is the Bishop of Rome, a position that makes him the leader of the worldwide Catholic Church . In the Catholic Church, the Pope is regarded as the successor of Saint Peter, the Apostle...

 and Andorra

Andorra

Andorra , officially the Principality of Andorra , also called the Principality of the Valleys of Andorra, , is a small landlocked country in southwestern Europe, located in the eastern Pyrenees mountains and bordered by Spain and France. It is the sixth smallest nation in Europe having an area of...

, the eldest son (Spain

Spain

Spain , officially the Kingdom of Spain languages]] under the European Charter for Regional or Minority Languages. In each of these, Spain's official name is as follows:;;;;;;), is a country and member state of the European Union located in southwestern Europe on the Iberian Peninsula...

) or eldest child (Belgium

Belgium

Belgium , officially the Kingdom of Belgium, is a federal state in Western Europe. It is a founding member of the European Union and hosts the EU's headquarters, and those of several other major international organisations such as NATO.Belgium is also a member of, or affiliated to, many...

, Denmark

Denmark

Denmark is a Scandinavian country in Northern Europe. The countries of Denmark and Greenland, as well as the Faroe Islands, constitute the Kingdom of Denmark . It is the southernmost of the Nordic countries, southwest of Sweden and south of Norway, and bordered to the south by Germany. Denmark...

, Netherlands

Netherlands

The Netherlands is a constituent country of the Kingdom of the Netherlands, located mainly in North-West Europe and with several islands in the Caribbean. Mainland Netherlands borders the North Sea to the north and west, Belgium to the south, and Germany to the east, and shares maritime borders...

, Norway

Norway

Norway , officially the Kingdom of Norway, is a Nordic unitary constitutional monarchy whose territory comprises the western portion of the Scandinavian Peninsula, Jan Mayen, and the Arctic archipelago of Svalbard and Bouvet Island. Norway has a total area of and a population of about 4.9 million...

, United Kingdom

United Kingdom

The United Kingdom of Great Britain and Northern IrelandIn the United Kingdom and Dependencies, other languages have been officially recognised as legitimate autochthonous languages under the European Charter for Regional or Minority Languages...

, and Sweden

Sweden

Sweden , officially the Kingdom of Sweden , is a Nordic country on the Scandinavian Peninsula in Northern Europe. Sweden borders with Norway and Finland and is connected to Denmark by a bridge-tunnel across the Öresund....

) of the current monarch fills the role of crown prince or princess, depending upon whether females of the dynasty

Dynasty

A dynasty is a sequence of rulers considered members of the same family. Historians traditionally consider many sovereign states' history within a framework of successive dynasties, e.g., China, Ancient Egypt and the Persian Empire...

 enjoy personal succession rights

Line of hereditary succession

Successor to hereditary title, office or like, in case of the heritage being indivisible, goes to one person at a time. There are also other sorts of order of succession than hereditary succession .The hereditary line of succession may be limited to heirs of the body, or may pass also to collateral...

.