Definition of PASTRY BAG
: a funnel-shaped container for holding soft food mixtures (as mashed potatoes, icing, or whipped cream) from which the foods are forced through a pastry tube at the tip in making ornamental spreads or decorations http://www.epicurious.com/tools/fooddictionar...pastry bag
A cone-shaped bag with two open ends. The small end is pointed and can be fitted with decorative tips of different sizes and designs, while doughs, whipped cream, fillings, etc. are spooned into the large end. When the bag is squeezed, the contents are forced through the tip. Pastry bags have a multitude of uses including decorating cakes, forming pastries or cookies and piping decorative borders. They come in various sizes and can be made of a variety of materials, including nylon and plastic-lined cotton or canvas, polyester and plastic. Pastry bags can be found in gourmet shops, some supermarkets and the kitchenware section of most department stores. http://en.wikipedia.org/wiki/Pastry_bag
A pastry bag
(or piping bag in the Commonwealth) is an often cone- or triangular-shaped, hand-held bag made from cloth, paper, or plastic that is used to pipe semi-solid foods by pressing them through a narrow opening at one end, for many purposes including cake decoration. It is filled through a wider opening at the opposite end, rolled or twisted closed, and then squeezed to extrude its contents.