WATERMARK
watermark
(noun) a distinguishing mark impressed on paper during manufacture; visible when paper is held up to the light
Source: WordNet® 3.1
Etymology
Noun
watermark (plural watermarks)
A translucent design impressed on the surface of paper and visible when the paper is held to the light.
(by extension) A logo superimposed on a digital image, a television broadcast, etc.
(computing) A value stored in a datafile to ensure its integrity, so that if the file's contents are changed then the watermark will no longer match the contents.
A mark indicating the level to which water has risen.
Verb
watermark (third-person singular simple present watermarks, present participle watermarking, simple past and past participle watermarked)
(transitive) To mark paper with a watermark.
(transitive) To mark a datafile with a digital watermark.
Source: Wiktionary
Wa"ter*mark`, n.
1. A mark indicating the height to which water has risen, or at which
it has stood; the usual limit of high or low water.
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.)
Definition: See Water line, 2. [R.]
Source: Webster’s Unabridged Dictionary 1913 Edition