Source : Webster's Revised Unabridged Dictionary (1913)

Phonogram \Pho"no*gram\, n. [Phono- + -gram.]
   1. A letter, character, or mark used to represent a
      particular sound.

            Phonograms are of three kinds: (1) Verbal signs,
            which stand for entire words; (2) Syllabic signs,
            which stand for the articulations of which words are
            composed; (3) Alphabetic signs, or letters, which
            represent the elementary sounds into which the
            syllable can be resolved.             --I. Taylor
                                                  (The
                                                  Alphabet).

   2. A record of sounds made by a phonograph.

Source : WordNet®

phonogram
     n : any written symbol standing for a sound or syllable or
         morpheme or word