An Etymological Dictionary of the German Language/Graf
Graf, m., ‘count, earl,’ from the equiv. MidHG. grâve (with the variant grœve, chiefly in the plur.), OHG. grâvo, grâvio (upon the old j form is based the ModHG. proper name Gräf, a parallel form of Graf). OHG. grâvio assumes a Goth. *grêfja (‘commander’), which is the term for the agent from the verbal noun gagrêfts, ‘command, order,’ preserved in Goth. The AS. term gerêfa (AS. scîrgerêfa, E. sheriff), which is similar in meaning, is yet radically different, since it points to a Goth. *ga-rôfja; its orig. sense is probably ‘head of a troop,’ allied to *rôf, OHG. ruova, OIc. róf (stafróf), ‘number.’ OIc. (MidE.), greife, ‘count,’ is derived from MidLG. grêve (from OLG. *grâfio). All explanations of Graf which do not originate in a Teut. root grêf, ‘to command,’ conflict with the laws relating to the change of sound and meaning. Note the signification of Graf in Du. pluimgraaf, ‘one who minds the fowls,’ Salzgraf, ‘manager of a saltwork,’ Deichgraf, &c.