What does Width mean?

The width of denim refers to its width after the weaving process and is basically divided into two categories: selvage denim and non-selvage, or regular, denim.

Heddels explains Width

Selvage denim is woven on a shuttle loom and is typically 75 cm wide. Jeans made with selvage denim have a nice, finished white edge along the inner seam of the trousers. On the other hand, regular denim is woven on a projectile loom and is 150 cm wide. Jeans made with this type of denim will fray along the seams unless the edge of the fabric is finished. Selvage denim is generally more expensive than regular denim because it must be woven on traditional shuttle looms that are not as efficient as modern projectile looms; however, many jean enthusiasts prefer it because of its quality and durability.

Additional Resources

Here is example of different width denim: