The Collaborative International Dictionary of English v.0.48:

Dotted \Dot"ted\, a.
   Marked with, or made of, dots or small spots; diversified
   with small, detached objects.
   [1913 Webster]

   Dotted note (Mus.), a note followed by a dot to indicate an
      increase of length equal to one half of its simple value;
      thus, a dotted semibreve is equal to three minims, and a
      dotted quarter to three eighth notes.

   Dotted rest, a rest lengthened by a dot in the same manner
      as a dotted note.
      [1913 Webster]

   Note: Notes and rests are sometimes followed by two dots, to
         indicate an increase of length equal to three quarters
         of their simple value, and they are then said to be
         double-dotted.
         [1913 Webster]