A croissant (meaning crescent) is a buttery flaky viennoiserie bread roll named for its well known crescent shape. Croissants and other viennoiserie are made of a layered yeast-leavened dough. The dough is layered with butter, rolled and folded several times in succession, then rolled into a sheet. The result is very similar to a puff pastry.
Crescent-shaped food breads have been made since the Middle Ages, and crescent-shaped cakes possibly since old times.
Croissants have long been a staple of French bakeries and pâtisseries. In the late 1970s, the development of factory-made, frozen, pre-formed but unbaked dough made them into a fast food which can be freshly baked by unskilled labour. Indeed, the croissanterie was explicitly a French response to American-style fast food, and today 30–40% of the croissants sold in French bakeries and patisseries are frozen.
Today, the croissant remains an essential ingredient of a continental breakfast.