early 13c., grome "male child, boy, youth." No known cognates in other Germanic languages. Perhaps from O.E. *groma, related to growan "grow;" or from O.Fr. grommet "servant" (cf. M.E. gromet "ship's boy," early 13c.). The fact is, it appeared 13c. and nobody knows from whence. Meaning "male servant who attends to horses" is from 1660s. The verb is first attested 1809; the transferred sense of "to tidy (oneself) up" is from 1843; figurative sense of "to prepare a candidate" is from 1887, originally in U.S. politics.
husband-to-be at a wedding, 1604, short for bridegroom (q.v.), from O.E. guma "man."