n. — Atlantic Canada, especially Nova Scotia & New Brunswick
a plastic bag.
Type: 3. Semantic Change — Sobeys is a grocery store chain founded in 1907, headquartered in Stellarton, Nova Scotia (see Sobeys reference). As Chart 1 shows, the term is restricted to Canada, with sole exposure in three provinces. The term Sobey's bag has been generalized in the Maritimes to refer to any plastic grocery bag (see Chart 2). The quotations below demonstrate how the term is used in lieu of the generic term plastic bag, which is preferred in Central and Western Canada.
The term is not listed in COD-2, Gage-5, ITP Nelson, DNE or DPEIE.
- Note that the food store chain Sobeys, much like Tim Hortons, dropped the apostrophe from its name.
Images:

Chart 1: Internet Domain Search, 20 Apr. 2016
Chart 2: Regional Domain Search, 7 Jun. 2016 (total n: only 6 hits)