from Wiktionary, Creative Commons Attribution/Share-Alike License.
- adjective Of or pertaining to
working-class professionsthat do not involve significant manual labor, such as skilled technicalprofessions, combining elements of blue-collarand white-collar.
from Wiktionary, Creative Commons Attribution/Share-Alike License
From gray and collar by extension of white-collar and blue-collar, perhaps with gray being seen as intermediate between white and blue.
"Traditionally, that was true, but for blue-collar and gray-collar [maintenance and custodial] jobs, the wages are now about the same in both sectors," he said.