In the 17th century, the first French explorers approached the great inland sea by way of the Ottawa River and Lake Huron; they referred to their discovery as le lac supérieur (the upper lake, i.e. above Lake Huron). Some 17th-century Jesuit missionaries referred to it as Lac Tracy (for Alexandre de Prouville de Tracy).[16] After taking control of the region from the French in the 1760s following their defeat in the French and Indian War, the British anglicized the lake's name to Superior, "on account of its being superior in magnitude to any of the lakes on that vast continent".[17]
(wikipedia: https://en.wikipedia.org/wiki/Lake_Superior)
It is still the largest lake by surface area.
While we're at it, Ontario used to be "Upper Canada" (from the POV of the Saint Lawrence river) and Quebec "Lower Canada". I.e. the naming scheme is even somewhat consistent.
You made it sound like "surface water" is literally just counting water close to the surface of the body of water, but it's basically any lake/river, so still impressive.
> Lake Baikal is the world's largest freshwater lake by volume, containing 22–23% of the world's fresh surface water, more than all of the North American Great Lakes combined. It is also the world's deepest lake, with a maximum depth of 1,642 metres (5,387 feet; 898 fathoms), and the world's oldest lake, at 25–30 million years.
That's a pretty deep lake..