A shield or flag usually consists of a field (= background) on which one or more distinct charges (= objects) are placed. The blazon of such a shield describes the field first, then the charges.
The field may be a single, solid tincture. In this case, it is described by simply naming the tincture. For example, the arms of Brittany consist of a field ermine with no charges on it. Thus:
To describe a group of charges, you usually specify at least three things:
For example, the following shield:
is blazoned "Sable, a mullet argent."
It is helpful to think of a shield as being painted in layers.
The field constitutes the first layer, and the first group of charges
is placed in a second layer on the field.
The following picture may help make this clear:
The illustration shows how "Sable, a mullet argent." might look if viewed obliquely from below.
To summarize the syntax rules so far: