A "medium" towel typically refers to a bath towel.

It is the most common and versatile size for drying the body after a shower or bath. While exact dimensions can vary slightly by brand, a standard bath towel generally measures around 27 to 30 inches in width and 52 to 58 inches in length (approximately 70 x 140 cm).

This size is considered "medium" because it is larger than a hand towel or washcloth but smaller than a larger bath sheet. It provides enough coverage to comfortably dry off while being easy to handle and store.