Roos is a surname with multiple origins.
In Dutch, Low German, Swiss German and Estonian “Roos” means “Rose” and the surname is often of toponymic origin (e.g. someone lived in a house named “the rose”).
[1] In 2007, 8600 people were named Roos and another 2880 “de Roos” in the Netherlands.
[2] In the UK, Roos may be of patronymic origin (“Andrews”) or indicating red hair (Old English “Rouse”).
[3] The name is also relatively common in Sweden (5,902 people in 2010), Finland (1219 in 2012)[4] and Estonia (934 people in 2019).