By my standards, if you can stand on one shore and see the other side, it’s not a lake. Though I suppose there are very few lakes by this definition.
Very few, especially as many of what most people call lakes are very much longer than they are wide. You can easily see from side to side across Cayuga Lake in New York, for example, but it about 40 miles long and a maximum of 435 feet deep.
Those of us living in the Great Lake region have an admittedly high standard for other lakes to live up to.
Here’s a typical view of Lake Ontario. It’s hard to think of a body of water as being “just” a lake when it stretches off beyond the horizon in three directions.
eta: Here’s a view from Olcott, NY. It’s one of the few areas where you can see across the lake (the short distance anyway). The buildings on the horizon are Toronto.
When I was taught biology as a lad in the 1970s in California in high school, our biology teacher asked this question. I answered, being the bright and eager kiss ass I was, that light penetrated to the bottom of a pond, but not a lake, having learned this answer from my parents who were, surprise, also high school biology teachers in California. The class was told that the hated Second Stone was indeed correct. Stopped watch and all.
The more I think about it, nearly every public body of water in my state is a Lake. Ponds are found in pastures with cows drinking from them. Or parks. Ponds are rarely shown on maps. They’re just tiny bodies of water.
I guess it’s different in other areas.