Source : Webster's Revised Unabridged Dictionary (1913)

Bluebottle \Blue"bot`tle\, n.
   1. (Bot.) A plant ({Centaurea cyanus}) which grows in grain
      fields. It receives its name from its blue bottle-shaped
      flowers.

   2. (Zo["o]l.) A large and troublesome species of blowfly
      ({Musca vomitoria}). Its body is steel blue.

Source : WordNet®

bluebottle
     n 1: an annual Eurasian plant cultivated in North America having
          showy heads of blue or purple or pink or white flowers
          [syn: {cornflower}, {bachelor's button}, {Centaurea
          cyanus}]
     2: blowfly with iridescent blue body; makes a loud buzzing
        noise in flight [syn: {Calliphora vicina}]