From the vocabulary word denoting the hardy, brightly coloured plant (Middle English hather; the spelling was altered in the 18th century as a result of folk etymological association with heath). The name was first used in the late 19th century and became particularly popular from the mid-1940s.
German and Jewish (Ashkenazic): nickname for a big man, from Middle High German grōz ‘large’, ‘thick’, ‘corpulent’, German gross. The Jewish name has been Hebraicized as Gadol, from Hebrew gadol ‘large’. This name is widespread throughout central and eastern Europe, not only in German-speaking countries.