The Collaborative International Dictionary of English v.0.48:

Frequence \Fre"quence\, n. [See Frequency.]
   1. A crowd; a throng; a concourse. [Archaic.] --Tennyson.
      [1913 Webster]

   2. Frequency; abundance. [R.] --Bp. Hall.
      [1913 Webster]

WordNet (r) 3.0 (2006):

frequence
    n 1: the number of occurrences within a given time period; "the
         frequency of modulation was 40 cycles per second"; "the
         frequency of his seizures increased as he grew older" [syn:
         frequency, frequence, oftenness]