0 a large area of water that has land all around it -- lago
Lake Windermere
1 an area of water surrounded on all sides by land -- lago [ masculine, singular ]
They went swimming in the lake. Ellos fueron a nadar en el lago.
Lake Ontario Lago Ontario
Both sides of a sea that was once a powerful civilisation's lake have everything to gain from this development.
We can improve many things, but we cannot turn a lake into an ocean.
The self-cleaning capacity of a lake and that of a sea are clearly different.