Wind Direction refers to the orientation of the labels on the liner, and which edge of the label will come off the roll first. This is only important if the labels will be applied with a labelling machine, and varies based on the make, model, style, etc of the machine. The instructions for the labelling machine will include the wind direction required to ensure the labels are applied correctly.
There are four options available, and they are most commonly referred to by numbers, but also by the edge that comes off first. These options are:
Wind Direction #1 - Top Off First
Wind Direction #2 - Bottom Off First
Wind Direction #3 - Right Off First
Wind Direction #4 - Left Off First