Definition of watermark

1. a pattern visible when paper is held up to light; it is pressed into the paper during manufacturing. For example, U.S. government stationery has the Great Seal of the United States in its watermark.
2. a faint pattern or second image added to a digital image for identification or other purposes.
3. an invisible code placed in a digital image to identify it. See invisible watermark.

graphic design impression made in paper during the papermaking process, consisting of an area that is slightly thinner and more translucent than the rest of the paper. The watermark is produced by a wire design on a roller called the dandy roll that is pressed against newly formed paper before most of the water content of the paper is removed. Watermarks are best viewed when the paper is held against light. They are used in high-grade paper to show the paper manufacturer's trademark or the grade of paper, or to show the paper user's logo or trademark, making the paper appear more distinctive and rich.