Lake
A contained inner life — emotion held in a known shape.
A lake in a dream is the dictionary's image of an inner life that is contained — known dimensions, a known edge. A clear still lake is the dream's image of emotional life in good order. A muddy lake is the dictionary's image of an emotional life that has been stirred without being addressed.
Where you often see it. A lake at dawn. A lake you have known. The dream uses the lake for a contained inner life — emotion held in a known shape.
What it is not. A lake is not the sea's smaller version. The dictionary reads it as bounded feeling — distinct, not lesser.
Related in the dictionary. Read lake with water, sea (the unbounded counterpart), and any scene of a feeling held without overflow.