The Collaborative International Dictionary of English v.0.48:

Fad \Fad\ (f[a^]d), n. [Cf. Faddle.]
   1. A hobby; freak; whim.
      [1913 Webster]

            It is your favorite fad to draw plans. --G. Eliot.
      [1913 Webster]

   2. a practise followed enthusiastically by a number of people
      for a limited period of time; as, the latest fad in
      fashion.

   Syn: craze; mania.
        [PJC] -- Fad"dist, n.
        -- Fad"dish, a.
        [1913 Webster]

WordNet (r) 3.0 (2006):

fad
    n 1: an interest followed with exaggerated zeal; "he always
         follows the latest fads"; "it was all the rage that season"
         [syn: fad, craze, furor, furore, cult, rage]

Moby Thesaurus II by Grady Ward, 1.0:

60 Moby Thesaurus words for "fad":
   best seller, big hit, boutade, brainstorm, brilliant success,
   capriccio, caprice, chic, conceit, crank, craze, crazy idea,
   crotchet, cry, faddiness, faddishness, faddism, faddist, fancy,
   fantastic notion, fantasy, flimflam, fool notion, freak,
   freakish inspiration, furore, gas, gasser, great success,
   harebrained idea, hit, humor, killing, kink, maggot, megrim,
   meteoric success, mode, momentary success, notion, novelty,
   passing fancy, quirk, rage, resounding triumph, riot,
   roaring success, sensation, smash, smash hit, style, toy, triumph,
   vagary, vogue, whim, whim-wham, whimsy, wow, wrinkle



The Free On-line Dictionary of Computing (30 December 2018):

FAD

   ["FAD, A Simple and Powerful Database Language", F. Bancilon
   et al, Proc 13th Intl Conf on VLDB, Brighton, England, Sep
   1987].