描图纸

[ noun ]
a semitransparent paper that is used for tracing drawings
<noun.substance>

Tracing \Tra"cing\, n.
1. 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.

2. A regular path or track; a course.

{Tracing cloth}, {Tracing paper}, 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.