day vs opacity

day

verb
  • To spend a day (in a place). 

noun
  • Rotational period of a planet (especially Earth). 

  • Any period of 24 hours. 

  • The part of a day period which one spends at one’s job, school, etc. 

  • A period from midnight to the following midnight. 

  • A period of contention of a day or less. 

  • A 24-hour period beginning at 6am or sunrise. 

  • A specified time or period; time, considered with reference to the existence or prominence of a person or thing; age; time. 

  • Part of a day period between sunrise and sunset where one enjoys daylight; daytime. 

opacity

noun
  • The state or quality of being opaque, not allowing light to pass through 

  • The state or quality of being inaccessible to understanding. 

  • A measure of relative impenetrability to electromagnetic radiation such as light. 

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