In Brandenburg Junker was originally the members of the higher edelfrei (immediate) nobility without or before the accolade. It evolved to a general denotation of a young or lesser noble, sometimes poor and politically insignificant , understood as "country squire".
As part of the nobility, many Junker families only had prepositions such as von or zu before their family names without further ranks. The abbreviation of Junker was Jkr., most often placed before the given name and titles, for example: Jkr. Heinrich von Hohenberg. The female equivalent Junkfrau (Jkfr.) was used only sporadically. In some cases, the honorific Jkr. was also used for Freiherren (Barons) and Grafen (Counts).
Junker was historically used across the German-speaking realm as a noble honorific, but since the 19th century, the designation became popularly associated with the landed nobility of the eastern part of the Kingdom of Prussia and its associated culture.
The title today survives in its traditional meaning in the Netherlands and Belgium in the Dutch form Jonkheer.
The term was also used in several countries in the title Kammerjunker, the German and Scandinavian (Danish, Norwegian and Swedish) equivalent of the French valet de chambre, a position usually given to young noble men in the service of a princely rank person at the court. A Kammerjunker was ranked below a chamberlain, but above a chamber page. Furthermore, the title has been used in military titles in the German and Scandinavian realm, such as Fahnenjunker and its Scandinavian equivalent fanejunker.
In Denmark, the term Junker connotes a young lord, originally the son of a duke or count in the Middle Ages, but also a term for a member of the privileged landowner class. Before 1375 the honorific was also suitable for Danish royal sons. It was also used in the title Kammerjunker within the royal household.
inside Germany, especially Brandenburg and Prussia, 'the Junkers' is a synecdoche for the nobility that controlled almost all of the land and government. With the formation of the German Empire in 1871, the Junkers dominated all of German government and the military. A leading representative was Prince Otto von Bismarck. 
- Duden; Meaning of Junker, in German. 
- William W. Hagen, Ordinary Prussians: Brandenburg Junkers and Villagers, 1500-1840 (2002).
- Henry VIII: September 1540, 26-30', Letters and Papers, Foreign and Domestic, Henry VIII, Volume 16: 1540-1541 (1898), p. 51. URL: http://www.british-history.ac.uk/report.aspx?compid=76214 Date accessed: 10 June 2012
- Rosenberg, 1943
- Francis Ludwig Carsten, A history of the Prussian Junkers (1989).