Source : Webster's Revised Unabridged Dictionary (1913)

Statistics \Sta*tis"tics\, n. [Cf. F. statistique, G. statistik.
   See {State}, n.]
   1. The science which has to do with the collection and
      classification of certain facts respecting the condition
      of the people in a state.

   Note: [In this sense gramatically singular.]

   2. pl. Classified facts respecting the condition of the
      people in a state, their health, their longevity, domestic
      economy, arts, property, and political strength, their
      resources, the state of the country, etc., or respecting
      any particular class or interest; especially, those facts
      which can be stated in numbers, or in tables of numbers,
      or in any tabular and classified arrangement.

Source : WordNet®

statistics
     n : a branch of applied mathematics concerned with the
         collection and interpretation of quantitative data and
         the use of probability theory to estimate population
         parameters

Source : Free On-Line Dictionary of Computing

statistics
     
         The practice, study or result of the
        application of mathematical {functions} to collections of
        {data} in order to summarise or {extrapolate} that data.
     
        The subject of statistics can be divided into descriptive
        statistics - describing data, and analytical statistics -
        drawing conclusions from data.
     
        (1997-07-16)