happy hour vs lacuna

happy hour

noun
  • A time of day, usually in the afternoon or early evening, when a bar or pub offers its drinks at a discounted price. 

  • Any small gathering, usually in the afternoon or early evening, set aside to relax and have a drink. 

  • Flowers. 

lacuna

noun
  • Any gap, break, hole, or lack in a set of things; something missing. 

  • A language gap, which occurs when there is no direct translation in the target language for a lexical term found in the source language. 

  • An absent part, especially in a book or other piece of writing, often referring to an ancient manuscript or similar. 

  • A space visible between cells, allowing free passage of light. 

  • A small blank space; a gap or vacancy; a hiatus. 

  • A small opening; a small pit or depression, especially in bone. 

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