A Coat of Arms

This describes the major constituent parts of a coat of arms

A Coat of Arms

A coat of arms may have originally meant a surcoat worn over armour showing the knight's armorial devices. Over the years it has come to mean loosely what is more formally known as the "personal or complete achievement" of arms: that is the design showing; shield, helm, mantling, crest, and perhaps supporters, motto, banner or flag.

Constituent Parts of the Heraldric Achievement

Helm, Wreath and Mantling
The style of helm shown was originally just what the knights wore at the time that particular coat of arms was granted. Later the designs moved to paper and became more stylised, with gold or silver trimmings, elabourate patterns, and ways of ranking the arms bearer - like the number of bars on the visor relating to rank.
The mantling represents the cloth that was attached to the back of the knight's helm and is in the two main colours (tinctures) of the arms.
The wreath is the twisted cord that held the mantling to the helm and again, is in the two main colours. The wreath could sometimes be a circlet - a metal band. Sometimes the wreath is combined with or replaced by a coronet. Coronets are simplified crowns, and suggested that the armiger had the uppers ranks of the aristocracy, a Duke or an earl, say.

Supporters and Motto
These parts are mainly associated with upper aristocracy and royalty, most older coats of arms dont have them. The figures each side are called supporters and as usual the right and left (Dexter and Sinister) is from the point of view of a person holding the shield, not as we look at it.
Mottos if the family had one, were below the shield in some countries (England) and above in others(Scotland).

The Crest
This is the most important heraldic part after the shield and it represented what was worn on the helm at tournaments. These could be very flashy with towers, horns, wings, human figures wind chimes/revolving plaques, bells, feathers, peacock feathers being most popular.

The Shield and Charges
This is the basic part of the arms. The background to the shield is often divided up into two colours in a number of commonly used patterns. The objects on the shield are known as the "charges" or "deivces".

Badge and Livery
Livery refers to the colours you might dress the faithful old retainers in - including your "company" of soldiers. The badge is some symbol that the retainers would wear, like an embroidered white rose for example. Feudal lords were more like to be known by their badges among the common people than by their full coat of arms.