Chain store and Drugstore

Chain store noun - One of a chain of retail stores under the same management and selling the same merchandise.

Drugstore and chain store are semantically related in place topic. In some cases you can use "Drugstore" instead a noun phrase "Chain store", when it comes to topics like business establishment that sells goods.

Drugstore noun - A retail store where medicines and miscellaneous articles are sold.

Chain store and drugstore are semantically related in place topic. You can use "Chain store" instead a noun "Drugstore", if it concerns topics such as business establishment that sells goods.