The word "Phonoscope" refers to an early motion picture viewer that was popular in the late 19th century. Synonyms for this word include "kinetoscope", "mutoscope", and "bioscope". These terms are all associated with early motion picture technologies and are interchangeable with "Phonoscope". They were all used to refer to various forms of peep show machines that were popular in the late 19th and early 20th centuries. While these technologies have become outdated with the advent of modern electronic media, the word "Phonoscope" remains an important part of the early history of cinema. So, these synonyms are still useful to explore the history and development of motion pictures.