Watermark

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.
	3.	(Naut.) See Water line, 2.

Noun	1.	watermark - a line marking the level reached by a body of water Synonyms: water line
	2.	watermark - a distinguishing mark impressed on paper during manufacture; visible when paper is held up to the light

Plimsoll line, Plimsoll mark, birthmark, blaze, blemish, blotch, brand, caste mark, check, checkmark, cicatrix, cut, dapple, discoloration, dot, earmark, engraving, fleck, flick, freckle, gash, graving, hack, high-water mark, jot, lentigo, load waterline, macula, mark, marking, mole, mottle, nevus, nick, notch, patch, point, polka dot, prick, puncture, scar, scarification, score, scotch, scratch, scratching, speck, speckle, splash, splotch, spot, stain, stigma, strawberry mark, tattoo, tattoo mark, tick, tidemark, tittle, waterline