Each single layer may be of a different, individual construction, whereas it can be a woven fabric, a unidirectional fabric or any other version. The choice of materials may be different. E.g. it could be a combination of Glass & Basalt, or Carbon & Kevlar & Glass.
In Multi-Axial Fabrics, often the manufacturer takes advantage of positioning the layers of fabric to where the main fiber direction points into a different angle to the previous or the following layer.
This allows for optimal utilization of the fiber properties, in most cases the strength requirements.
Following graph illustrates one example of a Muli-Axial Fabric:
A four layer Multi-Axial Fabric would be called a Quadraxial fabric. it Can have the main fiber direction of the layers point in 3 or four different directions (degrees).
The following graph illustrates the necessary stitching-assembly process.