The two main devices (symbols) in the Souter blazon are the cross crosslet fitchee and escutcheon. The two main tinctures (colors) are azure and argent.
Azure is the heraldic colour blue, usually quite a deep, dark shade of the colour (there is a lighter blue that sometimes occurs, known as celestial azure). If colour printing is not available then it can be represented by closely spaced horizontal lines in a scheme known as “hatching” 1Boutell’s Heraldry, J.P. Brooke-Little, Warne, (revised Edition) London 1970, P 26. The word is thought to originate from the Arabic lazura and it represents the colour of the eastern sky. It is also said to be the colour associated by the Catholic Church with the Virgin Mary and hence of particular significance 2The Symbolisms of Heraldry, W. Cecil Wade, George Redway, London, 1898 P150.
Argent is the heraldic metal Silver and is usually shown as very pure white. It is also known more poetically as pearl, moon (or luna) 3Understanding Signs & Symbols – Heraldry, S. Oliver & G. Croton, Quantum, London, 2013, P53. In a sketch or drawing it is represented by plain, unmarked paper 4A Glossary of Terms used in British Heraldry, J.H. Parker, Oxford, 1847, P11.
No other symbol appearing in heraldry is subject to as much variation as the cross 5Boutell’s Heraldry, J.P. Brooke-Little, Warne, (revised Edition) London 1970, P 47. Mediaeval Europe was a deeply religious and Christian and many of the nobility wanted to show their devotion by adopting the symbol of the cross as part of the arms. Since no two arms could be identical there arose many variants of the cross. The cross crosslet is one of these, having an additional cross bar on each arm. 6A Glossary of Terms used in British Heraldry, J.H. Parker, Oxford, 1894, Entry:Cross Crosslet Wade suggests that these additional crossing signify “the fourfold mystery of the Cross”. 7The Symbolisms of Heraldry, W. Cecil Wade, George Redway, London, 1898 P103 The final addition fitchee simply means pointed, and indicates that the lower end is pointed, as if it is to be struck into the ground. 8A Glossary of Terms used in British Heraldry, J.H. Parker, Oxford, 1894, Entry:Fitché
The escutcheon simply represents smaller shield shapes included within the shield, and its close relative, the inescutcheon is just a larger version occupying most of the field. 9A Glossary of Terms used in British Heraldry, J.H. Parker, Oxford, 1894, Entry:Escutcheon There is no particular significance that can accorded to the escutcheon itself, but attention should be paid to the colour and devices that are borne upon it. The escutcheon may also be added to an existing coat of arms either as recognition of some additional honour (an escutcheon of augmentation”) or in the case where arms that are already quartered are to be combined an escutcheon with the new arms may be placed overall (an ”escutcheon of pretence”). 10Boutell’s Heraldry, J.P. Brooke-Little, Warne, (revised Edition) London 1970, P 126 & 141