From WordNet (r) 2.0 (August 2003) [wn]:
margrave
n 1: the military governor of a frontier province in medieval
Germany
2: a German nobleman ranking above a count (corresponding in
rank to a British marquess)
From The Collaborative International Dictionary of English v.0.48 [gcide]:
Margrave \Mar"grave\, n. [G. markgraf, prop., lord chief justice
of the march; mark bound, border, march + graf earl, count,
lord chief justice; cf. Goth. gagr["e]fts decree: cf. D.
markgraaf, F. margrave. See March border, and cf.
Landgrave, Graff.]
1. Originally, a lord or keeper of the borders or marches in
Germany.
[1913 Webster]
2. The English equivalent of the German title of nobility,
markgraf; a marquis.
[1913 Webster]