symbol vs watermark

symbol

verb
  • To symbolize. 

noun
  • A type of noun whereby the form refers to the same entity independently of the context; a symbol arbitrarily denotes a referent. See also icon and index. 

  • A signalling event on a communications channel; a signal that cannot be further divided into meaningful information. 

  • An internal identifier used by a debugger to relate parts of the compiled program to the corresponding names in the source code. 

  • A character or glyph representing an idea, concept or object. 

  • A summary of a dogmatic statement of faith. 

  • The numerical expression which defines a plane's position relative to the assumed axes. 

  • A thing considered the embodiment of a concept or object. 

watermark

verb
  • To mark paper with a watermark. 

  • To mark a datafile with a digital watermark. 

noun
  • A mark indicating the level to which water has risen. 

  • A translucent design impressed on the surface of paper and visible when the paper is held to the light. 

  • A logo superimposed on a digital image, a television broadcast, etc. 

  • A value stored in a datafile to ensure its integrity, so that if the file's contents are changed then the watermark will no longer match the contents. 

How often have the words symbol and watermark occurred in a corpus of books? (source: Google Ngram Viewer )