What does Klaus mean?
Klaus is an uncommonly occurring given name for men but a very prominent last name for all people (#5944 out of 150436, Top 4%). (2000 U.S. Census)
Nicholas (#57 the previous year), Nils and Niklas are the popular alternative forms of Klaus (#unlisted) rated in the Top 1000. These boy names reached the apex of their popularity during 1900-1909 (usage of 0.3933%) and are somewhat less popular today (usage 0.3143%, down 20.1%). Below is a charted analysis of the popularity of Klaus and affiliated names. (2014 Birth Statistics)