Note

Musical symbols are the marks and symbols, used since about the 13th century in the musical notation of musical scores, styles, and instruments, in order to describe pitch, rhythm, tempo – and, to some degree, its articulation (e.g. a composition in its fundamentals). ... Note and rest values are not absolutely defined, but are proportional in duration to all other note and rest values. The whole note is the reference value, and the other notes are named (in American usage) in comparison; i.e. a quarter note is a quarter the length of a whole note. [List of musical symbols. Wikipedia]