dynasty

from WordNet (r) 3.0 (2006)

dynasty
    n 1: a sequence of powerful leaders in the same family

from The Collaborative International Dictionary of English v.0.48

Dynasty \Dy"nas*ty\ (d[imac]"nas*t[y^] or d[i^]n"as*t[y^]; 277),
   n.; pl. {Dynasties} (-t[i^]z). [Gr. dynastei`a lordship, fr.
   dynastey`ein to hold power or lordship, fr. dyna`sths: cf. F.
   dynastie dynasty. See {Dynast}.]
   1. Sovereignty; lordship; dominion. --Johnson.
      [1913 Webster]

   2. A race or succession of kings, of the same line or family;
      the continued lordship of a race of rulers.
      [1913 Webster]

from Bouvier's Law Dictionary, Revised 6th Ed (1856)

DYNASTY. A succession of kings in the same line or family; government; 
sovereignty.