The two main devices (symbols) in the Highmore blazon are the moorcock and cross bow. The two main tinctures (colors) are argent and sable.
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) 1Understanding Signs & Symbols – Heraldry, S. Oliver & G. Croton, Quantum, London, 2013, P53. In a sketch or drawing it is represented by plain, unmarked paper 2A Glossary of Terms used in British Heraldry, J.H. Parker, Oxford, 1847, P11.
Sable, the deep black so often found in Heraldry is believed to named from an animal of the marten family know in the middle ages as a Sabellinœ and noted for its very black fur 3A Glossary of Terms used in British Heraldry, J.H. Parker, Oxford, 1894, Entry:Sable. In engravings, when colors cannot be shown it is represented as closely spaced horizontal and vertical lines, and appropriately is thus the darkest form of hatching, as this method is known 4Boutell’s Heraldry, J.P. Brooke-Little, Warne, (revised Edition) London 1970, P 26. Although it may seem a sombre tone, and does indeed sometimes denote grief, it is more commonly said to represent Constancy 5The Symbolisms of Heraldry, W. Cecil Wade, George Redway, London, 1898 P35.
The Moor cock occurs in a number of coats of arms but always seems to be reference to the family name (e.g. MOORE) rather than having any special significance as a type of bird. 6A Glossary of Terms used in British Heraldry, J.H. Parker, Oxford, 1894, Entry:Moor-cock
Given the martial nature of the origins of Heraldry, in the identification of knights and men-at-arms it can come as no surprise that mediaeval weaponry of all types are frequently to be found in a coat of arms 7Boutell’s Heraldry, J.P. Brooke-Little, Warne, (revised Edition) London 1970, P 89. The cross bow is illustrated in its conventional form that we would still recognise today. In common with the simple bow, it can be taken as a symbol of “martial readiness”. 8The Symbolisms of Heraldry, W. Cecil Wade, George Redway, London, 1898 P111