Lakes, and which is the biggumest

The question was, what is the world's largest lake?
Well, Lake Superior was right if we went by surface area, which is of course a possible interpretation of the question. (But Superior, it's said, never gives up its dead.)

The other hair-splitting nerdomic interpretations could be largest enclosed body of salty water, or enclosed fresh water, which are the Caspian Sea and Lake Baikal respectively.

The Caspian Sea is the world's largest land-locked body of water. It contains approximately 18,900 cubic miles of water (78,700 cubic kilometers).

Lake Baikal is the world's largest freshwater lake in terms of volume. It contains about 5521 cubic miles of water (23,000 cubic kilometers), or approximately 20% of Earth's fresh surface water. This is a volume of water approximately equivalent to all five of the North American Great Lakes combined.

The largest lake in the United States is Lake Superior, one of the Great Lakes, located on the United States / Canada border. It is largest in both surface area 31,700 square miles (82,103 square kilometers) and in volume of water 2904 cubic miles (12,100 cubic kilometers).