As a boy's name this is a pet form of Jeremy or Gerald, or occasionally of Gerard and Jerome. As a girl's name it is a variant spelling of Gerry, and is sometimes bestowed as an independent given name, as in the case of the American model and actress Jerry Hall (b. 1956).
English: nickname for someone with gray hair or a gray beard, from Old English græg ‘gray’. In Scotland and Ireland it has been used as a translation of various Gaelic surnames derived from riabhach ‘brindled’, ‘gray’ (see Reavey). In North America this name has assimilated names with similar meaning from other European languages.