The Collaborative International Dictionary of English v.0.48:

nonmodern \nonmodern\ adj.
   1. not modern; of or characteristic of an earlier time.
      Opposite of modern. [Narrower terms: antebellum;
      fogyish, mossgrown, mossy, stick-in-the-mud(prenominal),
      stodgy old-fashioned; medieval, mediaeval, gothic;
      old-time, quaint; unmodernized; victorian;
      old-fashioned, outmoded; old-world] Also See: old,
      past.
      [WordNet 1.5]

The Collaborative International Dictionary of English v.0.48:

antebellum \antebellum\ adj.
   1. belonging to a period before a war, especially the
      American Civil War.
      [WordNet 1.5]

WordNet (r) 3.0 (2006):

antebellum
    adj 1: belonging to a period before a war especially the
           American Civil War