in sight vs seen

in sight

prep
  • Near or close in either distance or time. 

  • In a place where something can be seen. 

seen

verb
  • simple past tense of see; saw. 

  • To understand, to comprehend. 

noun
  • The letter س in the Arabic script. 

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