The definition of "orchestrion" given in Arthur Reblitz's "The Golden
Age Of Automatic Musical Instruments" (p. 407) -- which adopts the
definition in the Bowers Encyclopedia -- says an orchestrion is a

  "Self-contained automatic musical instrument, esp. a large one,
  equipped with several different instruments in imitation of an
  orchestra.  Usually contains some percussion effects (e.g., drums,
  cymbal, triangle, etc.)."

The definition enumerates four main types: Barrel orchestrion, Keyboard
piano orchestrion, Large keyboardless piano orchestrion, and Small
cabinet-style orchestrion.

The definition mentions that early manufacturers were prone to using
the term broadly in their advertising, sometimes calling such things as
disc music boxes, organettes, mechanical zithers, etc., "orchestrions."

Collectors today have more specific and more accurate names for such
instruments, although the general public may use the term as loosely
as they do "nickelodeon."

Matthew Caulfield (Irondequoit, N.Y.)