The Grammar of Heraldry/Chapter 2
The shield is divided by various lines drawn through it, as follows:—
The meaning of these terms will be understood by reference to the Ordinaries.
The partition lines dividing a shield are not always straight; they may assume any of the following forms:—
These last five, however, are seldom to be met with.
When a shield is blazoned as quaterly, it does not necesarily follow that it is divided into four portions. Fig. 24, for instance, would be described as quaterly of 10.