Source : Webster's Revised Unabridged Dictionary (1913)

Notebook \Note"book`\, n.
   1. A book in which notes or memorandums are written.

   2. A book in which notes of hand are registered.

Source : WordNet®

notebook
     n 1: a book with blank pages for recording notes or memoranda
     2: a small compact portable computer [syn: {notebook computer}]

Source : Free On-Line Dictionary of Computing

notebook
     
        1.  {laptop computer}.
     
        2.  {Labtech Notebook}.
     
        (1998-01-05)