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]

The Free On-line Dictionary of Computing (19 January 2023):

FAD

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