Monotype or Monoprint
The difference between monotypes and monoprints frequently baffles art buyers and sellers alike! Therefore, a description of that difference is useful.
A monotype is one of a kind, a unique piece of artwork. It is the simplest form of printmaking, requiring only pigments (ink), a surface on which to apply them, paper and some form of press. The image is made on a plate, either metal or plexiglass, and simply transfered to a piece of prepared paper by the pressure of a press.
All of my images are monotypes.
A monoprint is one of a series—therefore, not wholly unique. A monoprint begins with an etched plate, a serigraph, lithograph or collograph. This underlying image remains the same and is common to each print in a given series. Other means of adding pigment or design are then employed to make each print in the series slightly different. The series of monoprints has a limited number of prints and each is numbered.
(adapted from http://www.collectorsguide.com)