I. ˈwȯ-tər-ˌmärk, ˈwä- noun
Date: 1640
1. : a mark indicating the height to which water has risen
2. : a marking in paper resulting from differences in thickness usually produced by pressure of a projecting design in the mold or on a processing roll and visible when the paper is held up to the light ; also : the design of or the metal pattern producing the marking
II. transitive verb
Date: 1866
1. : to mark (paper) with a watermark
2. : to impress (a given design) as a watermark