Types of outlets

I am a Belgian student writing a thesis about the candy sector in the US. An important part of the thesis are the many types of outlets that sell candy. I have a problem understanding the difference between all of these types. Could somebody please explain the difference?

The most important outlets are: supermarkets, department stores, mass merchandisers, convenience stores, drugstores and grocery stores.

Is a supermarket an example of a mass merchandiser?

For example "The Simpsons": what type of store is the Kwik-E-Markt?

At the moment I see no difference between a convenience and grocery store.

I thought drugstores sold only drugs (medicine)

Etc

Thank you very much for your cooperation

[RonBee]

The most important outlets are: supermarkets, department stores, mass merchandisers, convenience stores, drugstores and grocery stores.

A mass merchandiser is a retailer that does a very high volume of business.

mass merchandisers: discount stores, chain drug stores, department stores. Also, some online companies (for example, eBay) qualify as mass merchandisers.

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[RonBee]

Is a supermarket an example of a mass merchandiser?

It could be if it is part of a chain of supermarkets that do a high volume of business.

For example "The Simpsons": what type of store is the Kwik-E-Markt?

Kwik-E-Markt is what is known as a convenience store.

At the moment I see no difference between a convenience and grocery store.

Convenience stores tend to be relatively small and connected to gas stations (filling stations).

I thought drugstores sold only drugs (medicine)

Drug stores sell much more than drugs. They are places where people can buy personal items and foodstuffs in addition to drugs. (To add to the confusion, many chain supermarkets have pharmacies.)

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