A score is typically composed of musical notation, with each instrumental or vocal component aligned vertically (meaning that concurrent events in the notation for each part are orthographically arranged). Sheet music produced for only one performer has sometimes been referred to as a "score." However, this usage is now rare. Sheet music produced for multiple performers is called an "orchestration." The word comes from the Greek organistrum, which means "instrument used to play in accompaniment of dancing" and refers to the fact that such music was often played at social gatherings. Early examples of orchestral music date back to the 16th century. By the 18th century, several terms were used to describe this type of music: "symphony," "sonata," "partita," and "march." Today, these terms are mostly applied to individual pieces rather than to entire compositions. Scores and Orchestrations may include graphic symbols and markings on the page as well as notes written out explicitly. These include bar lines, time signatures, and other indications of rhythmic structure. Textual marks include cues, directions, reminders, and any other information that does not fit naturally into the music itself but might be helpful to someone performing or listening to the music. The term "score" also applies to the document that contains all the information necessary to perform or record an arrangement or composition.