The Collaborative International Dictionary of English v.0.48:

Numeration \Nu`mer*a"tion\, n. [L. numeratio a counting out: cf.
   F. num['e]ration.]
   1. The act or art of numbering.
      [1913 Webster]

            Numeration is but still the adding of one unit more,
            and giving to the whole a new name or sign. --Locke.
      [1913 Webster]

   2. The act or art of reading numbers when expressed by means
      of numerals. The term is almost exclusively applied to the
      art of reading numbers written in the scale of tens, by
      the Arabic method. --Davies & Peck.
      [1913 Webster]

   Note: For convenience in reading, numbers are usually
         separated by commas into periods of three figures each,
         as 1,155,465; in continental Europe, periods are used
         for a similar division. According to what is called the
         "English" system, the billion is a million of millions,
         a trillion a million of billions, and each higher
         denomination is a million times the one preceding.
         According to the system of the French and other
         Continental nations and also that of the United States,
         the billion is a thousand millions, and each higher
         denomination is a thousand times the preceding.
         [1913 Webster +PJC]

WordNet (r) 3.0 (2006):

numeration
    n 1: naming numbers
    2: the act of counting; reciting numbers in ascending order;
       "the counting continued for several hours" [syn: count,
       counting, numeration, enumeration, reckoning,
       tally]