'Millennial' definitions:

Definition of 'millennial'

From: WordNet
adjective
Relating to a millennium or span of a thousand years [syn: millennial, millennian]

Definition of 'Millennial'

From: GCIDE
  • Millennial \Mil*len"ni*al\, a. Of or pertaining to the millennium, or to a thousand years; as, a millennial period; millennial happiness. [1913 Webster]