A mark showing the greatest height to which water has risen. A line indicating the heights of high and low tide. A translucent design impressed on paper during manufacture and visible when the paper is held to the light. The metal pattern that produces this design. Information directly encoded into the data portion of an image, video, or audio file that identifies the copyright owner or a licensed user. In image or video files, a watermark may be either visible or invisible. To mark (paper) with a watermark. To impress (a pattern or design) as a watermark. To insert (a digital file) with a watermark.