The head of government of Germany is called Chancellor (German: Kanzler). In German politics the position is equivalent to that of a Prime Minister in other countries. The latter term is not used, since its direct German equivalent, Ministerpräsident, is used exclusively for the heads of government of the states of Germany (called Länder in German).
The office of Chancellor has a long history, stemming back to the Holy Roman Empire. The title was at times used in several states of German-speaking Europe. The modern office of Chancellor was established with the North German Confederation, of which Otto von Bismarck became Chancellor (German, Bundeskanzler) in 1867. After unification of Germany in 1871, the office became known in German as Reichskanzler, although it continued to be referred to as Chancellor in English. With Germany's constitution of 1949, the title Bundeskanzler was revived in German.
The current Chancellor of Germany is Angela Merkel, who was elected in 2005. She is the first female Chancellor. In German she is thus known as Bundeskanzlerin. That word was never used officially before Angela Merkel, but it is a grammatically regular formation of a noun denoting a female.