Webster 1913 Edition
The act of one who traces; especially, the act of copying by marking on thin paper, or other transparent substance, the lines of a pattern placed beneath; also, the copy thus producted.
A regular path or track; a course.
specially prepared transparent cloth or paper, which enables a drawing or print to be clearly seen through it, and so allows the use of a pen or pencil to produce a facsimile by following the lines of the original placed beneath.
Webster 1828 Edition
Tracing lines, in a ship, are lines passing through a block or thimble, and used to hoist a thing higher.