logo vs watermark

logo

noun
  • A single graphic which contains one or more separate elements. 

  • An audio recording for the same purpose; a jingle. 

  • A visual symbol or emblem that acts as a trademark or a means of identification of a company or organization. 

  • An ensign, a badge of office, rank, or power. 

watermark

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

  • 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 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. 

verb
  • To mark paper with a watermark. 

  • To mark a datafile with a digital watermark. 

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