Ross

Scottish and English: habitational name from any of various places called Ross or Roos(e), deriving the name from Welsh rhós ‘upland’ or moorland, or from a British ancestor of this word, which also had the sense ‘promontory’. This is the sense of the cognate Gaelic word ros. Known sources of the surname include Roos in Humberside (formerly in East Yorkshire) and the region of northern Scotland known as Ross. Other possible sources are Ross-on-Wye in Herefordshire, Ross in Northumbria (which is on a promontory), and Roose in Lancashire

English and German: from the Germanic personal name Rozzo, a short form of the various compound names with the first element hrōd ‘renown’, introduced into England by the Normans in the form Roce.

German and Jewish (Ashkenazic): metonymic occupational name for a breeder or keeper of horses, from Middle High German ros, German Ross ‘horse’; perhaps also a nickname for someone thought to resemble a horse or a habitational name for someone who lived at a house distinguished by the sign of a horse.

Jewish: Americanized form of Rose 3.