A cowl is a long hooded robe with wide sleeves worn by members of some monastic orders. The term has also been adopted to refer to a wide range of coverings, from the cowl which covers the engine of a car to hoods used to cover chimneys, improving their draft and cutting down on errant sparks. You may also hear the word “cowl” in reference to a loose, hood-like neckline on a woman's garment. Cowl necklines are very popular on winter sweaters, offering insulation to the neck to keep the wearer comfortable in cold weather.
The word is derived from the Latin cucullus, which originally referred to a type of bag used to carry groceries. Over time, the word came to be used in reference to hoods, which were sewn in much the same style. While many people associate the cowl with an expression of religious faith today, early cowls were far more practical. Monks often lived in cold, drafty monasteries, and cowls kept them warm, reducing the risk of getting sick. They also acted as visual symbols as office, as cowls were only given to monks who had taken vows.
Cowls come in a wide range of colors, linked to various religious orders, and nuns wear a version of the cowl as well. The fabrics tend to be very plain, in keeping with religious injunctions against vanity, and they are typically dyed in a single color. Both monks and nuns may wear woven belts attached to rosaries, crosses, or other religious articles, and the hood is typically not worn, instead flowing over the back of the robe.
Depending on your cultural origins, you may also associate the cowl with Death, who is often depicted in a black cowl with the hood up, carrying his scythe of office. The formal hooded robes worn by academics at graduations also resemble the medieval cowl, although the hoods are usually multicolored, providing information about the accomplishments of the graduate and indicating the college that he or she is graduating from.
Because the cowl is such a well known part of religious iconography, it is not unusual to see a few children wearing various versions of the cowl at Halloween, dressing up as monks, nuns, or Death. Some costume shops sell cowls for this purpose, and it is also possible to make them at home. For an authentic touch, you should use a heavy natural fiber like wool, and you may want to line the cowl with cotton or silk for comfort. In addition to looking more accurate, the cowl will also keep its wearer warm on Halloween night, which often gets quite chilly.