There are a number of terms that are used for wide width fabrics and the most common is continuous. These fabrics don't require joins when used for curtains. The most common fabric types are sheers and voiles (see sheers and voiles category).
In some of the new ranges, there are wide width prints and spectacular burn outs. In the Living Naturally collection there are two fabrics (Utility and Equator) that are wide width in natural and linen looks that are perfect for soft romans and continuous curtains.