nocturnal vs vesper

nocturnal

adj
  • Taking place at night, nightly. 

  • Primarily active during the night. 

noun
  • A device for telling the time at night, rather like a sundial but read according to the stars. 

  • A person or creature that is active at night. 

vesper

adj
  • Evening. 

noun
  • A vesper bat. 

  • A vesper martini. 

  • The evening. 

  • The bell that summons worshipers to vespers; the vesper-bell 

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