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Webster 1913 Edition

Noun.

A bag for holding implements or materials for work; especially, a reticule, or bag for holding needlework, and the like.

workbag ‎(plural workbags)

A bag containing tools or material used for work, especially needlework.
- 2007 June 28, Lisa Belkin, “Your Briefcase Just Ran Over My Toe”, in New York Times:
  The American Medical Association warns that carrying more than 10 percent of your body weight can lead to injury, and the overnight appearance of low back pain led me to weigh my own workbag a few summers ago (back then, it was a satchel slung over one shoulder).