Very often we see cards that give nice bonuses or cashback for spending in "department stores."

Is there a specific definition of this term anywhere, or does it vary from credit card to credit card? If you Google the term, you find a lot of places come up that seem to stretch the definition, at least as I understand it.

Which of these are or are not in that category?:

Wal-Mart
Kohl's
Target
Sears
K-Mart
Big Lots
Bed, Bath, and Beyond
Dillard's
Meijer
Nordstrom's
and hundreds more

How can we be sure we are spending at a "department store?" It could make a huge difference to our strategies. Are we to contact every card issuer and ask for a list?