A farl (reduced form of the Scotsfardel) is any of various roughly triangular flatbreads and cakes, traditionally made by cutting a round into four pieces.
In Northern Ireland, the term generally refers to soda bread and potato bread or cakes (potato farls). While soda bread can be made like normal breads, it is made into farls for use in the Ulster fry. A farl is a flat piece of bread about 3/4 inch thick with a rough quarter-circle shape.
In Scotland today, the word is used less than in Northern Ireland, but a farl can be a quarter piece of a large flat scone, bannock, or oatcake. It may also be used for shortbread when baked in this particular shape.
The word may be related to fallaid in some way. However, the Dictionary of the Scots Language says that farl is a shorter form of fardel, the word once used in some parts of Lowland Scotland for "a three-cornered cake, usually oatcake, generally the fourth part of a round". In earlier Scots fardell meant a fourth or quarter.
A farl is made by spreading the dough on a griddle or frying pan in a rough circular shape. The circle is then cut into four equal pieces and cooked. Once one side is done the dough is flipped to cook the other side.