Source : Webster's Revised Unabridged Dictionary (1913)

Dynasty \Dy"nas*ty\ (?; 277), n.; pl. {Dynasties}. [Gr. ?
   lordship, fr. ? to hold power or lordship, fr. ?: cf. F.
   dynastie dynasty. See {Dynast}.]
   1. Sovereignty; lordship; dominion. --Johnson.

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

Source : WordNet®

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