Selvage and selvedge mean exactly the same thing - different companies spell it differently and there apparently is no "right" way to spell it. It comes from the phrase "self-
edge" which refers to the
edge being finished by the
loom instead of sewn together after weaving. thanks Geowu. Selvage is the term commonly used to refer to denim that has been produced on a shuttle loom. Since the amount of fabric produced from a shuttle loom is significantly narrower than a projectile (wide) loom, the cotton consumption is higher and the time required is greater. In selvage jeans, you
will see the actual
edge of the fabric where the weaving stops and is finished by the loom, as opposed to denim woven on a projectile loom, where the fabric has been cut off at the
ends. The "redline" selvage is
Levi's signature and was used in all their jeans up to 1982, before
Cone Mills nixed them for the more modern projectile looms, which are faster and much more efficient.