Rosenberg is a family name and toponym of German origin.
Its principal meaning is "mountain of roses", from Rose + Berg.
However, as a toponym, in some locations it may have originally meant "red mountain" or simply "red hill", from rot + Berg.
The terminal consonant of the /rot/-/roθ/-/roð/-/ros/ syllable has varied across regions and centuries; there are many variations of the name, including Rozenberg, Rotenberg, Rottenberg, Rothenberg and Rodenberg.
It is also a common name among Ashkenazi Jews.