German: topographic name for someone who lived at a place where wild roses grew (see Rose 1), with the suffix -er denoting an inhabitant.German (Röser): habitational name from places called Rös, Roes, or Rösa in Bavaria, Rhineland, and Saxony, or a variant of Rosser.Swiss German (Röser): from a short form of a Germanic personal name based on hrod renown.English: unexplained.