Where does the name marsupial come from?

The word "marsupial" comes from the Latin word "marsupium," which means "pouch."

This is a direct reference to the most defining characteristic of marsupials: the pouch, a fold of skin on the abdomen of the mother, which serves as a safe haven and incubator for their young.

So, the name essentially means "pouched animal," aptly describing the unique feature that sets them apart from other mammals.