Source : Webster's Revised Unabridged Dictionary (1913)

Illiteracy \Il*lit"er*a*cy\, n.; pl. {Illiteracies}. [From
   {Illiterate}.]
   1. The state of being illiterate, or uneducated; want of
      learning, or knowledge; ignorance; specifically, inability
      to read and write; as, the illiteracy shown by the last
      census.

   2. An instance of ignorance; a literary blunder.

            The many blunders and illiteracies of the first
            publishers of his [Shakespeare's] works. --Pope.