The Collaborative International Dictionary of English v.0.48:

Traditional \Tra*di"tion*al\, a. [Cf. F. traditionnel, LL.
   traditionalis.]
   1. Of or pertaining to tradition; derived from tradition;
      communicated from ancestors to descendants by word only;
      transmitted from age to age without writing; as,
      traditional opinions; traditional customs; traditional
      expositions of the Scriptures.
      [1913 Webster]

   2. Observant of tradition; attached to old customs;
      old-fashioned. [R.] --Shak.
      [1913 Webster]

WordNet (r) 3.0 (2006):

traditional
    adj 1: consisting of or derived from tradition; "traditional
           history"; "traditional morality" [ant: nontraditional,
           untraditional]
    2: pertaining to time-honored orthodox doctrines; "the simple
       security of traditional assumptions has vanished"

Moby Thesaurus II by Grady Ward, 1.0:

100 Moby Thesaurus words for "traditional":
   Christian, accepted, accustomed, acknowledged, admitted, ancestral,
   approved, authentic, authoritative, autobiographical, being done,
   biographical, canonical, chronologic, comme il faut, common,
   conformable, consuetudinary, conventional, correct, current,
   customary, de rigueur, decent, decorous, established, evangelical,
   everyday, faithful, familiar, firm, fixed, folk, formal,
   generally accepted, habitual, hagiographic, hallowed, handed down,
   heroic, historic, historied, historiographic, hoary, household,
   immemorial, inveterate, legendary, literal, long-established,
   long-standing, martyrologic, meet, mouth, mythological, normal,
   obtaining, of long standing, of the faith, of the folk, old, oral,
   ordinary, orthodox, orthodoxical, popular, prescribed,
   prescriptive, prevalent, proper, received, recognized, regular,
   regulation, right, ritual, rooted, routine, scriptural, seemly,
   set, sound, spoken, standard, stock, textual, time-honored,
   traditionalistic, tried and true, true, true-blue, understood,
   unwritten, usual, venerable, verbal, well-known, widespread,
   wonted, worshipful