noun (n)

• a tiny or scarcely detectable amount(noun.quantity)

  Synonym:
  iota, scintilla, shred, smidge, smidgen, smidgeon, smidgin, tittle
  

  source: wordnet30
• The smallest part or particle imaginable; a bit; a jot; an iota; -- generally used in an adverbial phrase in a negative sentence.(noun)

  source: webster1913