small line for placing notes above and below the stave.
a short line; a notation for extending the range above or below the staff
an extension of the staff
a short line added above or below normal staff lines to indicate notes of extra-high or -low pitch
A short line used to extend the staff.
A small line written above or below the staff to extend its range.
A leger line or ledger line is a tool of musical notation to express notes that do not fall on the regular lines or spaces of the musical staff. A short line (slightly longer than the note) is drawn parallel to the lines on the staff (above or below as appropriate), corresponding to where the staff line would be if the note were in range (see Figure 1).