Klaus is the German short form of Nikolaus, the German Nicholas, which comes from the Greek Nikolaos and means "victory of the people". It was one of the most common German boys' names of the mid-20th century, and American children know it from Santa Claus, which has the same root. In the United States Klaus is a rare choice: it ranked number 4309 in 2000, reached number 1880 in 2022 and stood at number 2245 in 2025.