What does the word bluebottle mean?

Usage examples for bluebottle

  1. It was evidently one of her bluebottle days. – The Unbearable Bassington by Saki
  2. " I do not believe that it is a bluebottle fly," exclaimed the emperor. – Andreas Hofer by Lousia Muhlbach
  3. They fed upon this soup, this gruel, and a surplus dripped to the ground below, where the bluebottle drank eagerly. – The Mad Planet by Murray Leinster