Definition of: watermark

(wô′tər·märk′, wot′ər-) noun
1. A mark showing the extent to which water rises; especially, the line marking the limit of the ebb and flow of the tide.
2. A series of translucent lines, letters, or designs made in paper by shaping the wires of the dandy rolls over which the paper passes while still in a pulpous state; also, the metal pattern which produces these markings.
—v.t.
1. To impress (paper) with a watermark.
2. To impress as a watermark.