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]