The Collaborative International Dictionary of English v.0.48:

Logogram \Log"o*gram\, n. [Gr. lo`gos word + -gram.]
   A word letter; a phonogram, that, for the sake of brevity,
   represents a word; as, |, i. e., t, for it. Cf.
   Grammalogue.
   [1913 Webster]

WordNet (r) 3.0 (2006):

logogram
    n 1: a single written symbol that represents an entire word or
         phrase without indicating its pronunciation; "7 is a
         logogram that is pronounced `seven' in English and
         `nanatsu' in Japanese" [syn: logogram, logograph]