Source : Webster's Revised Unabridged Dictionary (1913)

Miscount \Mis*count"\, v. t. & i. [Cf. OF. mesconter, F.
   m['e]compter. Cf. {Miscompute}.]
   To count erroneously.

Miscount \Mis*count"\, n. [Cf. F. m['e]compte error, OF.
   mesconte.]
   An erroneous counting.

Source : WordNet®

miscount
     n : an inaccurate count
     v : count wrongly