What are ledger lines?
A ledger line or leger line is used in Western musical notation to notate pitches above or below the lines and spaces of the regular musical staff. A line slightly longer than the note head is drawn parallel to the staff, above or below, spaced at the same distance as the lines within the staff.
What is the meaning of lines in music?
a. a succession of notes forming a distinctive sequence; tune. b. the horizontally represented aspect of the structure of a piece of music.