The Collaborative International Dictionary of English v.0.48:

Chiliad \Chil"i*ad\, n. [Gr. chilia`s, chiliado`s, fr. chi`lioi
   a thousand.]
   A thousand; the aggregate of a thousand things; especially, a
   period of a thousand years.
   [1913 Webster]

         The world, then in the seventh chiliad, will be assumed
         up unto God.                             --Sir. T.
                                                  More.
   [1913 Webster]

WordNet (r) 3.0 (2006):

chiliad
    n 1: the cardinal number that is the product of 10 and 100 [syn:
         thousand, one thousand, 1000, M, K, chiliad,
         G, grand, thou, yard]