The surname Rasmussen (sometimes Rasmusen) is a Danish an Norwegian surname, meaning "Rasmus' son". The first name "Rasmus", from which it is derived, is itself a contraction of "Erasmus" the name of a famous 16th Century philosopher and theologian. When found elsewhere, i.e. in North America and Australia, the name "Rasmussen" is a likely indication of Scandinavian family origin, though that might be generations removed.