lubber's line

lubber line also lub·ber's line  (lbrz)

n.

A line or mark on a mariner's compass or cathode-ray indicator that represents the heading of a ship or aircraft.

Thesaurus

Noun

1.

lubber's line - a fixed line on a ship's compass indicating its heading lubber line, lubber's mark, lubber's point point of reference, reference point, reference - an indicator that orients you generally; "it is used as a reference for comparing the heating and the electrical energy involved"