ledger line

American Heritage® Dictionary of the English Language, Fourth Edition

1. n. Music A short line placed above or below a staff to accommodate notes higher or lower than the range of the staff.

Century Dictionary and Cyclopedia

1. n. In angling, an arrangement of fishing-tackle in which the lead rests on the bottom.

Wiktionary

1. n. A musical notation to inscribe notes outside the lines and spaces of the regular musical staves; a line slightly longer than the note is drawn parallel to the staff, above or below, spaced at the same distances as the notes within the staff.

GNU Webster's 1913

1. n. See Leger line, under 3d Leger, a.

WordNet 3.0

1. n. a short line; a notation for extending the range above or below the staff