The Collaborative International Dictionary of English v.0.48:

April \A"pril\, n. [L. Aprilis. OE. also Averil, F. Avril, fr.
   L. Aprilis.]
   1. The fourth month of the year.
      [1913 Webster]

   2. Fig.: With reference to April being the month in which
      vegetation begins to put forth, the variableness of its
      weather, etc.
      [1913 Webster]

            The April's her eyes; it is love's spring. --Shak.
      [1913 Webster]

   April fool, one who is sportively imposed upon by others on
      the first day of April.
      [1913 Webster]

WordNet (r) 3.0 (2006):

April
    n 1: the month following March and preceding May [syn: April,
         Apr]