Source : Webster's Revised Unabridged Dictionary (1913)

Fiftieth \Fif"ti*eth\, a. [AS. f[=i]ftigo[eth]a. See {Fifty}.]
   1. Next in order after the forty-ninth; -- the ordinal of
      fifty.

   2. Consisting of one of fifty equal parts or divisions.

Fiftieth \Fif"ti*eth\, n.
   One of fifty equal parts; the quotient of a unit divided by
   fifty.

Source : WordNet®

fiftieth
     adj : the ordinal number of fifty in counting order [syn: {50th}]
     n : position 50 in a countable series of things