The term "Gladstone bag" is named after the British Prime Minister William Ewart Gladstone (1809-1898). This type of bag was popular during his time and became associated with his name, although he did not invent it nor was he specifically known for using it.

A Gladstone bag is characterized by its rigid frame and hinged opening at the top, which allows it to open widely for easy access to the contents inside. The bag's robust construction and practical design made it a popular choice for travelers, professionals, and notably doctors, who needed a reliable and spacious bag to carry their medical instruments and supplies.

The term "doctor's bag" refers to the usage of the Gladstone bag by medical professionals. Over time, the bag's association with doctors became so strong that it is often specifically referred to as a doctor's bag. The Gladstone bag's durability and practicality made it an ideal choice for doctors who required a portable and sturdy bag for their tools and medications.