Plainchant or plainsong, the traditional monodic chant of the Catholic Church, still uses a four-line stave, and in earlier music the number of lines used varied.

素乐或素——传统单音颂，依旧采四线谱，早期音乐中，线目各不相同。

Noteheads may be black (a circular or oval shape filled in) or white and are used on the staff to indicate pitch. The shape of noteheads has differed historically, as in plainchant.

符头可以是黑（圆形或卵形）或白，在五线谱上以表明音高。符头形状在历史上有很多种，比如在单音颂中。