A crest is a component of a heraldic display, so called because it stands on top of a helmet, as the crest of a jay stands on the bird's head.
The earliest heraldic crests were apparently painted on metal fans, and usually repeated the coat of arms painted on the shield, a practice which was later discontinued. Later they were sculpted of leather and other materials.
Originally, the crest was often "continued into the mantling", but today the crest normally stands within a wreath of cloth, called a torse, in the principal tinctures of the shield (the liveries). Various kinds of coronet may take the place of the torse, though in some unusual circumstances the coronet sits atop a torse, and is defined as either all or part of a crest. The most frequent crest-coronet is a simplified form of a ducal coronet, with four leaves rather than eight. Towns often have a mural crown, i.e. a coronet in the form of embattled stone walls.
Objects frequently borne as crests include animals, especially lions, normally showing only the fore half; human figures, likewise often from the waist up; hands or arms holding weapons; bird's wings. In Germany and nearby countries, the crest often repeats the liveries in the form of a tall hat, a fan of plumes in alternating tinctures, or a pair of curving horns. The horns may have a hole in the tip to hold a cluster of plumes or flowers, and because of this have been imported to English heraldry at least once as elephant's trunks.
Crests are not normally borne by women, or clergy, at least not in the UK, because they did not participate in war or tournaments and thus would not have a helm on which to wear it. An exception is the reigning queens of England or Britain, whose armorial display is indistinguishable from that of kings.
Some armigers used their crest as a personal badge, leading to the erroneous use of the word "crest" to describe a shield or full coat of arms. Such badges are often used by members of Scottish clans. These Scottish crest badges can be used where clan members, who are not armigerous, wear a badge consisting of a clan chief's crest and motto/slogan encircled by a belt and buckle. These crest badges are often erroneously called "clan crests". Even though clan members may purchase and wear such badges, the crest and motto/slogan remain the heraldic property of the clan chief.
A Scottish crest badge is a heraldic badge worn to show allegiance to an individual or membership in a specific Scottish clan. Crest badges are commonly called clan crests, but this is a misnomer; there is no such thing as a collective clan crest, just as there is no such thing as a clan coat of arms.
Crest badges consist of a crest and a motto/slogan. These elements are heraldic property and protected by law in Scotland. Crest badges may be worn by anyone; however, those who are not entitled to the heraldic elements within, wear a crest badge surrounded by a strap and buckle. Those who own the heraldic elements within, may wear a crest badge surrounded by a plain circlet. The strap and buckle represents that the wearer is a follower of the individual who owns the crest and motto.
Crest badges are commonly worn by members of Scottish clans. These badges usually consist of elements from the clan chief's coat of arms. Clan members who wear their chief's crest and motto surrounded by a strap and buckle, show they are a member of the chief's clan (family). There are established clans that do not have chiefs recognized by the Lord Lyon King of Arms. In such cases clan members sometimes wear the crest badge of the last known chief. Some clans wear crest badges derived from the arms of individuals who were never recognized as clan chiefs. Although "clan crests" are commonly bought and sold, the heraldic crest and motto belong to the chief alone and never the individual clan member.
Crest badges, much like clan tartans, do not have a long history, and owe much to Victorian era romanticism, having only been worn on the bonnet since the 19th century. The original badges used by clans are said to have been specific plants worn in bonnets or hung from a pole or spear.