Original: A BÃ 1\/4 chner flask, also known as a vacuum flask, filter flask, side-arm flask or Kitasato flask, is a thick-walled Erlenmeyer flask with a short glass tube and hose barb protruding about an inch from its neck.
Simplified: A BÃ 1\/4 chner flask (also called a vacuum flask, a filter flask, a side-arm flask or a kitasato flask) is a flask made of glass.