Ritter

Ritter (German for "knight") is a designation used as a title of nobility in German-speaking areas. Traditionally it denotes the second-lowest rank within the nobility, standing above "Edler" and below "Freiherr" (Baron). For its historical association with warfare and the landed gentry in the Middle Ages, it can be considered roughly equal to the titles of "Knight", but is hereditary so is closer to the British title of "Baronet". The wife of a Ritter was called a "Frau" (in this sense "Lady") and not Ritterin.
As with most titles and designations within the nobility in German-speaking areas, the rank was hereditary and generally was used with the nobiliary particle of von or zu before a family name. In heraldry, from the late 18th century a Ritter was often indicated by the use of a coronet with five points, although not everyone who was a Ritter and displayed arms made use of such a coronet. In the Austrian Empire and Austria-Hungary the title of "Ritter von" was bestowed upon citizens who deserved more than the plain "von" but were not considered deserving enough as to be given a barony as "Freiherr". 
Even today, members of the Central European Order of St. George, which goes back to Emperor Maximilian and was later reactivated by Habsburg after its dissolution by Nazi Germany, are "Ritter" (knights).
In addition to the described system, Württemberg introduced orders of merit beginning in the late 18th century which also conferred nobility as "Ritter von" but kept the title limited to the recipient's lifetime (see Military Order of Max Joseph).