2. A letter, device, or the like, wrought into paper during
the process of manufacture.
Note: ``The watermark in paper is produced by bending the
wires of the mold, or by wires bent into the shape of
the required letter or device, and sewed to the surface
of the mold; -- it has the effect of making the paper
thinner in places. The old makers employed watermarks
of an eccentric kind. Those of Caxton and other early
printers were an oxhead and star, a collared dog's
head, a crown, a shield, a jug, etc. A fool's cap and
bells, employed as a watermark, gave the name to
foolscap paper; a postman's horn, such as was formerly
in use, gave the name to post paper.'' --Tomlinson.
3. (Naut.) See {Water line}, 2. [R.]