The name Claus is a boy's name of Scandinavian origin. Claus and is often added to lists like Royal Baby Names and discussed in our forums with posts like "Sibset makeover game! B/G pairs".
From the experts:
A very Christmassy name, for obvious reasons. And how is Mrs. Claes, Class, Klaas, Klasse, Klaus (Dutch), Clause, Klaus (German), Launo (Finnish)?