It's a bit more complicated than that. At SCS we combine ISO and FTC definitions. In the example cited, our interpretation would hinge on two factors. 1) is the glass from the original manufacturer no longer of a quality sufficient to be used in the the product produced at that plant? In other words, does it qualify as waste? 2) Does it go through a re-processing step before it can be used as feedstock? In other words, is something done to it before it can be used in the second plant? If the answer is 'yes' to both questions, it is clearly recycled. This is the basic definition, but it can become more nuanced and convoluted from here.