The Collaborative International Dictionary of English v.0.48:

Necropolis \Ne*crop"o*lis\, n.; pl. Necropolises. [NL., fr.
   Gr. ?; nekro`s a dead body, adj., dead + ? city.]
   A city of the dead; a name given by the ancients to their
   cemeteries, and sometimes applied to modern burial places; a
   graveyard.
   [1913 Webster]

WordNet (r) 3.0 (2006):

necropolis
    n 1: a tract of land used for burials [syn: cemetery,
         graveyard, burial site, burial ground, burying
         ground, memorial park, necropolis]