sel'-vej (qatsah): The word occurs only in the description of the tabernacle (Ex 26:4; 36:11). It has reference to the ten curtains which overhung the boards of the sanctuary. Five of these formed one set and five another. These were "coupled" at the center by 50 loops of blue connected by "clasps" (which see) with 50 others on the opposite side. The "selvedge" (self-edge) is the extremity of the curtain in which the loops were.
⇒See the definition of selvedge in the KJV Dictionary